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Final Report

CARE Innovative Action

Preliminary Study

on

Integration of Unmanned Aerial

Vehicles into Future Air Traffic

Management

Version 1.1

7th December 2001

Industrieanlagen-Betriebsgesellschaft mbH

Dept. Airborne Air Defence

Einsteinstr. 20

D-85521 Ottobrunn

Preliminary Study CARE INNOVATIVE ACTION

Integration of Unmanned Aerial Vehicles into future Air Traffic Management

Date: 10.12.01

Executive Summary

Today Air Traffic Management (ATM) is closely related to safe and economic air

transportation. Looking at the huge number of daily conducted flights this implies a

tremendous task. The situation is expected to become more complicated in near future since

air traffic is increasing steadily and, despite the recent events, is expected to follow this trend

in the next decades. This demands enormous efforts to maintain safe and economic ATM

services within the available, limited airspace in recognition of all environmental constraints.

The situation is aggravated by various development programmes for Unmanned Aerial

Vehicles (UAV), which various operators will claim for integration into ATM rather soon.

Currently the military UAV market is growing with increasing pace. Recent UAV applications

in military conflict zones have numerously demonstrated that UAV technology meanwhile

have achieved a considerable level of production standard and reliability in many areas.

As such UAV key-technologies which are also applicable to civil UAVs are mainly available

or at least under development. These technologies offer a wide range of potential civil

applications like support of search and rescue activities, environmental surveillance, pollution

detection, weather monitoring, fire monitoring, mapping, coastal and border surveillance and

control, surveillance of infra-structural facilities (pipelines, airports, railways, roads,

waterways, etc.), airborne telecommunication relay-station and airborne crime

reconnaissance.

However, the civil UAV market has not yet started significantly. Main restraints for that can

be identified as follows:

• Certification Procedures and Regulations for civil UAVs are currently almost undefined.

• Air Traffic Management Regulations and Procedures for a commonly used airspace

environment which allows the operation of civil UAVs have not been developed.

These items lead to the innovative spirit of this study:

By investigation of the impact of UAV operations on Air Traffic Management (ATM), problem

and conflict areas between UAVs and other related traffic have to be identified in order to

develop adequate air traffic management procedures which will provide the initial

environment for the integration of such vehicles into ATM. As a further result of this approach

the corresponding design requirements for UAVs can be identified.

Consequently, this study helps to evolve the civil UAV market to start from the technology

spin-off out of current military development and technology.



Date: 10.12.01

Contents

1 Introduction........................................................................................................................ 12

2 Motivation and Innovation of the Study ............................................................................ 17

3 Current UAV-Systems and Programs – Status and Trends ............................................ 20

3.1 Overview of present UAV Programmes ....................................................................... 20

3.2 UAV Classification......................................................................................................... 21

3.3 Overview of Present UAV Systems and Programmes ................................................. 22

3.3.1 Illustration of the UAV Categorisation.................................................................... 24

3.4 Operation Control .......................................................................................................... 27

3.4.1 Air Traffic Control (ATC) ........................................................................................ 27

3.4.2 UAV Control Stations (UCS).................................................................................. 27

3.4.3 Data Link ................................................................................................................ 29

3.4.4 Navigation System................................................................................................. 33

3.4.5 Flight Management System................................................................................... 33

3.4.6 Other Relevant Equipment..................................................................................... 33

3.5 Consideration of Achievable Flight Path Accuracy ...................................................... 33

3.5.1 Preliminary Classification Scheme for Accuracy of Trajectory ............................. 33

3.6 Preliminary Assessment of Failure Modes ................................................................... 34

3.6.1 General Description of the Failure Mode Table..................................................... 34

3.6.2 Function Areas for Failure Mode Assessment ...................................................... 35

3.6.3 Phases of Flight ..................................................................................................... 36

3.6.4 Modes of Operation................................................................................................ 37

3.6.5 Severity Categorisation.......................................................................................... 38

4 Impact of UAV Operations on ATM.................................................................................. 40

4.1.1 UAV Flights within Controlled Airspace................................................................. 41

4.1.2 UAV Flights within Uncontrolled Airspace............................................................. 45

4.1.3 UAV Operations within Special Use Airspace....................................................... 46

4.2 Provision of Separation and Collision Avoidance......................................................... 46



Date: 10.12.01

4.2.1 Basic Regulations for Separation and Collision Avoidance.................................. 46

4.2.2 Separation Safety................................................................................................... 47

4.3 Procedures for UAV Hand-Over and Border Crossing................................................. 49

4.4 Ground Operations........................................................................................................ 50

4.4.1 Guidance and control by the UCS......................................................................... 51

4.4.2 Independent surveillance function, performed by ATC (Ground control) ............. 51

4.5 Military Operations ........................................................................................................ 52

4.6 Flight Termination System (FTS).................................................................................. 52

5 Proposed ATM Requirements .......................................................................................... 53

5.1 ATM Requirements ....................................................................................................... 53

5.1.1 UAV operations in existing air route scheme (IFR)............................................... 53

5.1.2 UAV operations outside existing air route scheme (off airways). ......................... 54

5.1.3 UAV operations in uncontrolled air space. ............................................................ 54

5.2 Procedures .................................................................................................................... 55

Impact of UAV Ops on ATM.............................................................................................. 56

ATM Requirement / Procedure ......................................................................................... 56

5.3 Integration of UAV into different Airspace Categories.................................................. 59

5.3.1 Definition of Decisive Features and UAV Integration Effort .................................. 59

5.3.2 UAV Integration into Present Airspace Classes.................................................... 61

5.3.3 UAV Integration into Future Airspace Categories ................................................. 63

6 Follow-up Study Proposal ................................................................................................. 65

6.1 Contents and Objectives ............................................................................................... 65

6.2 Simulation Tools ............................................................................................................ 66

6.2.1 MILSIM Simulation Environment ........................................................................... 66

6.2.2 Extended Air Defence Testbed.............................................................................. 68

7 References........................................................................................................................ 69

8 Appendix A – Tables of UAV............................................................................................ 71

8.1 Explanation of data fields and used abbreviations ....................................................... 71



Date: 10.12.01

8.1.1 Illustration of the UAV Categorisation.................................................................... 83

9 Appendix B – Representative Examples for UAV............................................................ 85

9.1 Class 0 - SCOUT 2000 ................................................................................................. 85

9.2 Class 1 - KZO (Brevel).................................................................................................. 87

9.3 Class 1 - OUTRIDER.................................................................................................... 89

9.4 Class 2 - PREDATOR................................................................................................... 91

9.5 Class 3 - Global Hawk................................................................................................... 93

10 Appendix C - Examples of Datalinks ................................................................................ 95

10.1 UAV “Mücke” ............................................................................................................. 95

10.2 UAV KZO / BREVEL................................................................................................ 96

10.3 UAV PIONEER.......................................................................................................... 97

10.4 UAV CL 289.............................................................................................................. 98

10.5 UAV Global Hawk...................................................................................................... 99

10.6 UAV Predator.......................................................................................................... 100

11 Appendix D – Airspace Categorisation........................................................................... 101

11.1 Air Traffic in European Airspace ............................................................................. 101

11.1.1 Basic Terms ..................................................................................................... 101

11.1.2 Airspace Classification..................................................................................... 102

11.2 Utilisation of European Airspace............................................................................. 103

11.2.1 Controlled Airspace.......................................................................................... 103

11.2.2 Uncontrolled Airspace...................................................................................... 105

11.2.3 Special Use Airspace....................................................................................... 105

12 Appendix E - Collision Avoidance................................................................................... 107

12.1 ACAS / TCAS / ETCAS ........................................................................................... 107

12.2 ADS-B...................................................................................................................... 108

12.3 Avoidance of Collision with Terrain ......................................................................... 108

13 Appendix F - Separation Safety...................................................................................... 109

Categorisation of manned Aircraft according to their Approach speeds (ICAO)........... 130



Date: 10.12.01

14 Appendix G - Detailed Description of Data Link ............................................................. 132

14.1 Description of Data Link .......................................................................................... 132

14.1.1 Function of Data Links: .................................................................................... 132

14.1.2 Characteristics of Data Links ........................................................................... 136

15 Appendix H - Preliminary Table of Failure Modes.......................................................... 141

16 Appendix I - Hand-Over and Border Crossing ............................................................... 144

17 Appendix J - Autonomous Flight..................................................................................... 146

17.1 Drones ..................................................................................................................... 148

17.2 Autonomy State 1, - No autonomy.......................................................................... 149

17.3 Autonomy State 2 – Autonomous manoeuvring, collision avoidance .................... 150

17.4 Autonomy State 3 – Autonomous, limited AI pilot available ................................... 151

17.5 Autonomy State 4 – Fully autonomous with sophisticated AI-Pilot available......... 153



Date: 10.12.01

List of Abbreviations

A/C Aircraft

ACARS Airborne Communications Addressing and Reporting System

ACAS Airborne Collision Avoidance System

ADC Air Data Computer

ADF Automatic Direction Finding

ADS-B Automatic Dependent Surveillance Broadcast

AGL Above Ground Level

AIC Aeronautical Information Circular

AIP Aeronautical Information Publication

AIS Aeronautical Information Services

AMSL Above Mean Sea Level

ASDE Airport Surface Detection Equipment

ATC Air Traffic Control

ATM Air Traffic Management

ATS Air Traffic Service

BLOS Beyond Line of Sight

CARE Co-operative Actions of R&D in EUROCONTROL

CDTI Cockpit Display of Traffic Information

CFIT Controlled Flight Into Terrain

COM Communication

CPA Closest Point of Approach

CPDLC Controller Pilot Data Link communication

CRC Cyclic Redundancy Check

CTR Control Zone

CVFR Controlled VFR

DGPS Differential GPS

DME Distance Measuring Equipment



Date: 10.12.01

DoD Department of Defence

DSSS Direct Sequence Spread Spectrum

EAD European AIS Database

ECAC European Civil Aviation Conference

EFIS Electronic Flight Information System

EGPWS Enhanced Ground Proximity Warning System

EO / IR Electro Optical / Infra Red

ESARR Eurocontrol Safety Regulations Requirements

ETCAS Enhanced TCAS

FAA Federal Aviation Authority

FHSS Frequency Hopping

FIS Flight information Service

FL Flight Level

FMS Flight Management System

FTS Flight Termination System

GCS Ground control Station

GNSS Global Navigation Satellite System

GPS Global Positioning System

HALE High Altitude Long Endurance

HF High Frequency

HMI Human Machine Interface

IAF Initial Approach Fix

IAS Indicated Air Speed

ICAO International Civil Aviation Organisation

IFF Identification Friend Foe

IFR Instrument Flight Rules

IFR Instrumental Flight Rules

IMC Instrumental Meteorological Conditions



Date: 10.12.01

INS Inertial Navigation System

Kbps Kilo bit per second

KIAS Knots Indicated Airspeed

LOS Line of Sight

LRE Launch And Recovery Element

MALE Medium Altitude Long endurance

MASPS Minimum Aviation Systems Performance Standard

Mbps Mega bit per second

MCE Mission Control Element

MMI Man Machine Interface

MMI Man Machine Interface

MOA Military Operation Area

MOPS Minimum Operational Performance Standards

MSL Medium Sea Level

MTOW Aircraft Maximum Take-Off Weight

NAVAID Navigational Aid

NAVAID Navigational Aids

NLOS Non Line of Sight

NOTAM Notice To Airmen

PIREP Pilot Report

PPR Prior Permission Required

P-RNAV Precision – Area Navigation

RA Resolution Advisory

RA Radio Altimeter or Resolution Advisory

RAIM Receiver Autonomous Integrity Monitoring

RNAV Area Navigation

RNP Required Navigation Performance

RTCA Radio Technical Commission for Aeronautics



Date: 10.12.01

RVSM Reduced Vertical Separation Minima

SAR Search and Rescue / Synthetic Aperture Radar

SATCOM Satellite Communication

SID Standard Instrument Departure

SIGINT Signal Intelligence

SSR Secondary Surveillance Radar

SST Super Sonic Transport

STAR Standard Arrival Route

STCA Short Term Conflict Alert

STOL Short Take Off and Landing

SUA Special Use Airspace

T/O Take Off

TA Traffic Advisory

TAWS Terrain Awareness and Warning System

TCAS Traffic Collision Avoidance Systems

TDMA Time Division Multiplex Access

TMA Terminal Control Area

TOW Take Off Weight

TRA Temporary Reserved Airspace

TUAV Tactical UAV

UAV Unmanned Air Vehicle

UCAV Unmanned Combat Air Vehicle

UCS UAV Control Station

VFR Visual Flight Rules

VHF Very High Frequency

VMC Visual Meteorological Conditions

VMC Visual Meteorological Conditions

VOR VHF Omni-directional Radio Range



Date: 10.12.01

VOR/DME Very High Frequency Omnidirectional Radio Range / Distance Measuring

Equipment

VTOL Vertical Take Off and Landing



Date: 10.12.01

1 Introduction

Today the idea of Air Traffic Management (ATM) is closely related to safe and economic air

transportation. Looking at the huge number of daily conducted flights this implies a

tremendous task. The situation is expected to become more complicated in near future since

air traffic is increasing steadily and, despite the recent events, is expected to follow this trend

in the next decades. This demands enormous efforts to maintain safe and economic ATM

services within the available airspace.

This touches another contradicting factor to higher airspace utilisation - the limitation of

resources. The airspace, frequencies for communication and data link are physically limited.

Another limiting factor is given by environmental constraints. Such constraints may result

from adverse weather conditions and even regulations and procedures of the ATM itself

imply limitations to the utilisation of airspace. An example for this is the fixed system of air

traffic routes and special procedures for noise reduction which are required in order to

minimise the impact of air traffic on the environment.

A new challenge which is already in progress will deteriorate this situation in the near future

and will introduce new aspects and dependencies to the current situation – Unmanned Aerial

Vehicles (UAV)1. Figure 1-1 provides an overview of the current situation:

Figure 1-1 - Factors influencing the Integration of UAVs into future ATM.

1 UAV is an abbreviation for “Unmanned Aerial Vehicle”. Some literature understand UAV as “Uninhabited Aerial

Vehicle” which refers to a technical equivalent meaning.

Unmanned Aerial VehiclesGrowing Number, Limited Reliability / Redundancy, Needs for ATM, etc.

Provision of High Quality ATM to Ensure Safe andEconomic Conduction of Air Transport

IncreasingDensity

ofAir Traffic

LimitedResources

Airspace,Data Link,

Frequencies,etc

Environ-mental

Constraints



Date: 10.12.01

Today a considerable number of development programmes for unmanned aerial vehicles are

rapidly progressing towards operational application. These programmes meet a large variety

of different applications, civil and military. In some areas even new operational aspects

(tasks) can be identified for future UAV applications which never have been dedicated to

manned flight. These areas are mainly derived from the UAV-typical abilities:

• to stay airborne for a couple of days in high altitudes,

• to be able for operations with high risk for damage or loss of aircraft withoutendangering the operation crews life,

• to perform flights with lightweight vehicles with much less costs than required for a fullpiloted aircraft.

These features allow many new beneficial UAV-applications, some of which are not even

thought about and need still adequate time for development. This trend is strongly supported

by technical improvements especially miniaturisation and improvements of technical

reliability. As such the market for UAV, both civil and military, is expected to see a very

strong increase.

As a spin-off from development for military applications the civil UAV market will envisage a

wide field for future UAV applications, e. g.:

• Support of Search and Rescue Activities,

• Environmental Surveillance / Pollution Detection / Weather Monitoring

• Fire Monitoring / Fire Fighting,

• Mapping,

• Coastal- / Border-Surveillance and Control,

• Surveillance of Infra-Structural Facilities (Pipelines, Airports, Railways, Roads,Waterways, Channels, High Tension Cables, etc.),

• Airborne Telecommunication Relay-Station,

• Airborne Crime Reconnaissance.

Since the technology required for such operations has been already prepared in most cases

for current military applications, the introduction of these UAV operations does not depend on

unavailable technology still to be developed. Instead these UAV applications mainly were

delayed by current shortfalls in certification requirements and missing procedural concepts

for the integration of UAVs into a commonly used airspace.

In summary these UAV development programmes will end up in an increasing demand for

airspace utilisation very soon, which need immediate measures to be taken in order to

support this request with adequate guidelines for the development and equipment of UAV.

The general aim of this effort is to enable the ATM system to guarantee the safe and orderly

flow of total air traffic (conventional air traffic and UAV traffic) under the new circumstances.



Date: 10.12.01

Actually there are two major areas identified which require more investigation to enable the

ATM system to be adequately prepared for this task:

• Establishment of common airworthiness requirements and according regulations forUAV,

• Establishment of common air traffic regulations and standardisation and derivedprocedures for adequate integration of UAV into Air Traffic Management Systems.

The first point involves national and international airworthiness authorities which should be

well aware that future airworthiness standards for UAV need to cover a wide range of

different applications – from the remotely controlled helicopter to large high altitude UAV,

autonomously cruising with sub-sonic speed with endurance of several days.

The second point addresses also the major focus of this study. It is important to note that

there are many cross-links between airworthiness and equipment requirements and the

corresponding air traffic procedures which could be utilised for an UAV. An example is

accuracy and reliability of the altitude information provided for the flight control system. Even

the cruise flight of a pre-programmed UAV requires accurate keeping of a given flight level. If

no other separation criteria to other related traffic are introduced, the equipment of the UAV

has to meet the requirements necessary in order to maintain the separation criteria for flight

safety reasons. Autonomous flight (Appendix J) includes also reactive measures,

autonomous and / or remote, of the UAV taken in order to avoid collisions with other related

traffic.

As such the effort spent for the integration of UAV into future air traffic management systems

is twofold: airworthiness requirements for the UAV and its equipment can directly be derived

if the ATM procedures, regulations and requirements are identified which the vehicle has to

comply with.

This reflects to the key idea of this preliminary study: The integration of UAV into future ATM

shall comply as best as possible with current standards and regulations. The overall aim of

the integration of UAV into future ATM should be to minimise the impact on other air traffic

regulations.

Initial start point of the study is an analysis and classification of current UAV systems and

future trends in order to identify main applications and related flight performance parameter

as mass, airspeed, endurance, altitude, manoeuvrability and flight task specific items. Very

important is the accuracy achievable in order to maintain a given flight path and the

corresponding reliability. This analysis shall also take into account the situation for possible

system failures and failure-identification. The failures for typical UAV of the identified classes

under consideration shall be analysed and categorised depending on their possible impact

on accuracy of maintaining an intended flight path.



Date: 10.12.01

Figure 1-2 shows a possible future integration of UAV in an ATM environment. Very

important for integration into air traffic management is the technical reliability and redundancy

of the navigation and flight control systems and of the data link to the UAV control station and

especially to the ATC organisations. For UAVs a new and very important aspect has to be

taken into account which is the communication or data link between ATC and the UAV

control authorities. This control station may be ground based or even airborne as well. As

such a wide variety of different conceptual approaches for the data link between ATC and

control station is possible. The air traffic control authority (ATC) and the UAV Control Station

(UCS), which performs the remote control of the UAV, form the initial network which enables

basic functionality for controlled flight of an UAV in a controlled airspace. The UAV itself may

be also active part of an data exchange network among other air traffic participants via TCAS

or ADS-B, for example. For safety reasons a back-up data-link between UAV Control station

and ATC is foreseen.

Air TrafficControl (ATC)UAV Control Station (UCS)

Ground COM

ADS B / TCAS ...

Figure 1-2 - Integration of UAV in an ATM environment

This first step into the investigation of this study will provide the following information:

• Range and variation between different UAV parameters with respect to their ability forintegration into ATM,

• Impact of system failures on flight path accuracy,

• Categorisation by means of flight task / mission applications.



Date: 10.12.01

This information provides supporting evidence for the second step of the study: an analysis

which impact of UAVs with various technical features could be expected on ATM. In addition

to analysis of UAV operations under normal (non-failure) conditions this investigation also will

be based on the failure assumptions for UAVs. The aim of this work is to briefly identify areas

of possible conflicts with other related traffic and as such to highlight resulting environmental

constraints for other related traffic. Such areas need further investigation and adequate

procedures for de-conflicting to be developed. In addition adequate level of information for

identification for ATM purposes is to be determined by these results.

This reflects the aim of the third step of this study, which mainly is focussed on work out of

ATM requirements and according procedures which enable UAVs for the integration into

ATM. These procedures should include all sections of a flight beginning with ground control,

taxi, take-off, climb, cruise, special task related issues for UAVs, descent, approach and

landing. For each section procedures for normal operation and for operation under failure

cases which may have impact on ATM-relevant parameter are to be taken into account.

According to the definition of UAV-procedures, the associated technical design-requirements

which UAVs have to meet become evident in order to achieve an adequate level of safety

and reliability for the UAV-integration into ATM. The workout of these ATM-related

requirements for UAVs requires a detailed coupling to recent airworthiness standards

respectively proposals for standards and as such is foreseen to be performed in the main

study due to time and funding constraints for the preliminary study.

This report is structured according to the step-wise approach described above. Following a

short description of the motivation and idea for this study in the next chapter, chapter 3 is

dedicated to the technical features of current UAVs and UAV development programmes with

special focus to ATM-relevant parameter like mass, airspeed, max. altitude, climb rate,

endurance, max. mission radius and data link (communications as addressed in Figure 1-2).

Chapter 4 of this study addresses possible conflict areas between UAVs and other related

traffic and subsequent impacts of hypothetical UAV-operations on ATM. These conflicts may

either be the result of different technical performance parameters between e. g. airliners and

UAVs or it could also be induced by special operations or manoeuvres required for the UAV

operation task (e. g. air launch from another carrier aircraft).

Chapter 5 of this study identifies possible air traffic procedures and requirements applicable

to the ATM-integration of UAVs with various technical features.

Chapter 6 presents the expected results of a proposed follow-on study based on the results

of this preliminary study and the funding. In order to estimate possible risks of this follow-on

study the feasibility will be analysed and stated.



Date: 10.12.01

2 Motivation and Innovation of the Study

Currently the military UAV market is growing with increasing pace. Most dominant

applications for military UAVs are reconnaissance and surveillance trials which often imply

long duration of flight in combination with high altitudes. The absence of on-board pilots in

these environmental conditions allows the UAV-design to be more stringent to that purpose.

Featuring a higher level of autonomy the UAV reduces the requirements to the pilot skills of

the UAV operator.

A very sound argument for military UAV is that pilots do not have to risk their lives especially

in the so called „high risk“-missions.

Besides that, the application of smaller UAVs may also reduce the costs per mission.

An outlook for the military UAV market confirms the enormous growth potential:

• Chairman of US Senate Armed Services Committee proposed in 2000 that a third of

deep-strike aircraft should be unmanned by 2010 [ 7].

• The world market for UAVs will experience growth throughout the forecast period 1998 to

2008. Revenues for the total market in 1998 reached approximately $2.1 billion [ 8].

• Americas military spends $1.2 billion a year on UAV research [ 7].

• US Air Force representative John Warden expects that 90 % of combat aircraft will be

unmanned by 2025 [ 7].

These figures clearly indicate that UAV development activities are in progress in a wide

range or even have been performed already. Recent UAV applications in military conflict

zones have numerously demonstrated that UAV technologies meanwhile have achieved a

considerable level of production standard in many areas.

As such UAV key-technologies which are also applicable to civil UAVs are mainly available

or at least under development. However, the civil UAV market has not been started

significantly.

This is also cormfirmed by a current UAV market analysis, see also ref.[ 8]:

“While the military market segment will continue to support substantial revenue growth for the

UAV industry, the greatest challenge facing civil market growth remains with the difficulty in

establishing, co-ordinating and implementing airspace regulation that applies to all UAV

varieties. This is the greatest restraint of world-wide market growth, as case by case local



Date: 10.12.01

flight clearance and hard-to-obtain liability coverage restrict the ability of manufacturers to

demonstrate system capabilities.”

In summary the main restraints for that process are:

• Certification Procedures and Regulations for civil UAVs are currently almost undefined.

• Air Traffic Management Regulations and Procedures for an commonly used airspace

environment which allows the operation of civil UAVs have not been developed.

This addresses to the innovative spirit of this study:

By investigation of the impact of UAV operations on Air Traffic Management (ATM), problem

and conflict areas between UAVs and other related traffic have to be identified in order to

develop adequate air traffic management procedures which will provide the initial

environment for the integration of such vehicles into ATM. As a further result of this approach

the corresponding design requirements for UAVs can be identified.

Consequently, this study helps to evolve the civil UAV market to start from the technology

spin-off out of current military development and technology.

An interesting side aspect of this study results out of the analysis of data link protection,

integrity and security technologies for the UAV link to the control station (UCS). More than

any other manned aircraft UAVs have to rely on the data link to the UCS for reasons of safe

operation in the commonly used airspace. An analysis of the applicability of these features

for civil air traffic is of general value for the overall safety and robustness of ATM systems in

the light of increasing security needs due to terrorism threat.

Due to the large variety of possible civil UAV applications, as outlined in the introduction of

this report, the need for provision of an adequate air traffic control environment for UAVs will

materialise very soon.

An early indication for that may be the current planning of several research and development

programmes which intentionally will cover some of these aspects. A good example of such

activities is the EU-funded study “USICO” which will be started by April 2002. This approach

features a collaborative research investigation on the integration of a representative UAV

type into ATM. As such this study will intentionally support to improve the understanding how

to operate and certify such type of UAV in order to meet the requirements to be fit for flying in

a commonly used airspace.

Complementary to that USICO-approach this study initially starts from the assumption that

future civil UAVs may fulfil quite different tasks. For that reason the level of treatment and

care provided from ATC authorities has to be analysed and subsequently adopted and



Date: 10.12.01

balanced with the special kind of operation. This study will provide an overview of possible

near future UAV applications and an assessment of proposed corresponding ATM-

procedures, the USICO-study will provide a perspective of work to be performed in order to

achieve ATM integration at hand of a selected type of UAV.

Due to this complementary character the USICO-study will be supported by the results of this

preliminary study in agreement with Eurocontrol.

In the following, some initial examples indicate a taste of the variety of future civil UAV

applications :

• In the ARM (Atmospheric Radiation Measurement) programme by US Department of

Defence and the US Department of Energy, UAVs were used together with manned

aircraft

• NASA has proposed to use UAV to aid Hawaiian coffee growers and to research how

lightning forms and dissipates during thunderstorms

• A Sidney based team has proposed an interactive entertainment concept, where

customers pay to virtually fly using a combination of UAV, the internet and simulation

technologies

• At the university of Stuttgart (Germany) advanced concepts exist to use stratospheric

airships UAVs as relay stations for the new UMTS communication network. Thus the

need for a huge number of additional ground based transmitter/receiver stations can be

reduced considerably. The all electric airships will be powered by a mutual dependent

combination of solar generation and fuel cell. The technique works at least at laboratory

level.



Date: 10.12.01

3 Current UAV-Systems and Programs – Status and Trends

A precondition for an adequate integration of UAVs into an ATM-environment is knowledge

about the variety and dominance of such UAV-parameters which determine the ability for the

integration into the commonly used airspace. These parameters are:

• UAV design parameters (mass, speed range, climb and descent rate,manoeuverability, endurance),

• equipment of the UAV (avionics / sensors, on-board flight control system, control datalink),

• reliability and robustness of the overall design (failure tolerant design, redundancy,graceful degradation),

• operational environment of the UAV (UAV-control station, data link to UAV and ATC).

Among these factors UAVs feature a very important topic with regard to ATC, which is the

non-availability of an on-board pilot. This requires high reliability of the data link to the UAV,

and in case of loss of data link, a sufficient level of autonomy of the UAV.

Following the intention of this study this chapter intentionally introduces such technical

aspects of current and near future UAVs, their corresponding control station environment and

a brief overview of their possible failures on system level with regard to such failures which

may induce an impact on ATM.

3.1 Overview of present UAV Programmes

In order to be integrated into ATM systems UAVs will have to conform to ATM-regulations

and procedures especially to comply with safety requirements. For that purpose a technical

overview of UAV and current UAV programmes has to focus on such technical features

which may influence the level of accuracy of keeping an intended flight path. These areas

are:

• the redundancy and reliability of equipment (flight control system, navigation system,communication/data links, propulsion system),

• flight mechanic performance parameter (max. altitude, airspeed, climb rate, range,endurance, manoeuverability),

• the method and quality of guidance (remotely piloted, remotely guided),

• the communication/data link triangle between ATM, vehicle control station and vehicleincluding devices for the data exchange,



Date: 10.12.01

• impact of system failures on operational aspects and system reaction.

At the first glance the large variety of different UAVs prevents a clear identification of the way

forward towards integration of UAV into air traffic management. For that purpose adequate

criteria for classification of UAV into groups or classes are required which basically could be

used to establish conformance to current ATM-procedures and requirements.

A very basic but important key feature is the method applied for the steering and controlling

of the vehicle. Actually there is a twofold development:

• Remotely controlled / piloted UAV:Such systems are basically steered by an active operator from a ground or air basedcontrol station. These systems induce normally a reasonable high workload to theoperator and require all ATC-related data exchange (incl. communication) with thatremote-controlling operator. Currently there is only a small number of such vehicles(e.g. PREDATOR-System incl. operator control and steering box ).

• Remotely guided UAV:Such systems have a high level of integrity and normally apply automatic flight controlalgorithms for the steering and controlling of the vehicle. On-board flight managementsystems allow the systems to operate autonomous for standardised / pre-setapplications. Within that environment the remote operator acts mainly as a systemmonitor and guides the vehicle via flight-task and way-point setting operations. TheATC-related data exchange will be performed partly by the on-board system itself (e.g.position, flight intention) and partly by the remote operator who will act mainly forclearance acceptance and to solve problems or unexpected events.

A more detailed separation of the different levels of autonomy is introduced in the Appendix J

- Autonomous Flight. Currently, the mainstream of UAV development adhere to the remotely

guided UAV principles. In the near future the trend to higher autonomy of the vehicle will

maintain and as such the remotely controlled / piloted UAV will decrease. This aspect

indicates that the method of control may not be an adequate scheme for a classification of

UAV.

From that viewpoint a classification is introduced using of flight mechanic basic parameters

and performance parameters. In the following a classification scheme is introduced based on

the maximum take-off weight and an additional categorisation based on the propulsion

system.

3.2 UAV Classification

The classification proposed below is based on the maximum take-off weight (max. TOW) of

the air vehicle, similar to manned aircraft. These weight categories correlate very well with

other classifications criteria like range, mission radius and maximum flight altitude.

Classifications based on the type of mission, like tactical UAV (TUAV), combat UAV (UCAV)

etc., or based on altitude and endurance, like MALE (medium altitude long endurance) or



Date: 10.12.01

HALE (high altitude long endurance), which are often used by military customers are less

relevant for ATM.

UAV Class

max TOW

[kg] Range Category

Typical Radiusfor Tasks

[nmi]

Typicalmax Altitude

[ft]

Class 0 Below 25 Close Range below 10 1000

Class 1 25 - 500 Short Range 10 - 100 15000

Class 2 501 - 2000 Medium Range 101 - 500 30000

Class 3 Above 2000 Long Range Above 500 Above 30000

Table 3-1 Classification of UAVs by maximum Take-off Weight

Beside this overall classification, sub-criteria like type of propulsion system (piston engine,

turboprop or turbojet), number of engines and type of lift system (fixed wing or rotor), can be

used for more detailed description.

3.3 Overview of Present UAV Systems and Programmes

Tables A1, A2, A3 and A4 in appendix A provide information on representative UAV systems

of western countries, like USA, Canada, Europe and Israel. The selected UAV are in service

or under development. To give an outline of the future, some study projects are included, too.

Nevertheless, many UAVs are available today or will be made available within the next

decade from further countries like Russia, South Africa, Turkey, Czech Republic, Croatia,

Brazil, Australia, China, Japan, India and South Korea.

Nearly all UAVs operate pre-programmed based on defined way-points and specified

payload/sensor control schedules. Furthermore, nearly all UAVs systems provide a

continuous remote control of the air vehicle through data-links between the platform and the

UAV control station (UCS). This control covers monitoring of the air vehicle, control of the

mission by adapting/changing the way-points and control of the payload. In some cases, a

direct manual control of the UAV by the operator based on down-linked onboard video and

position data – for instance as an emergency procedure for approach and landing – is

provided, too.

For most UAVs the mission radius is limited by the range of the Line of Sight (LOS) data-

links. The radius can be increased by airborne communication relay stations and satellite

communication, which may use the same platform as the mission UAV. In 2010 high

performance communication relay systems installed on HALE UAV will be available which

allow further increased ranges of the UAV without the need of satellite communication.



Date: 10.12.01

Representative UAV of Class 0 (below 25 kg)

This class covers very small, close range UAV which are summarised in Table A1 for

information only, as this type of UAV is not relevant for ATM.

Representative UAV of Class 1 (25 to 500 kg)

In this class many UAVs are available (Table A2). Most of these are military UAVs which are

used for reconnaissance, surveillance and target acquisition / designation. These UAVs are

primarily driven by internal combustion engines (piston or rotary) with pusher or tractor

propeller. With this type of propulsion the flight velocity is limited to 150 – 200 kts. For higher

speeds, small turbojets are used, resulting in much lower endurance.

Due to antenna size, weight and cost the UAVs of this class are not equipped with satellite

communication systems. Hence, the mission radius is normally limited to the data-link LOS

range (e.g. 100 nmi). Navigation is primarily based on GPS or DGPS. In some cases inertial

navigation systems (INS) with GPS update are installed.

Representative UAV of Class 2 (501 to 2000 kg)

In this class we will find most of the medium range, medium altitude endurance UAVs (Table

A3). A mission radius of up to 500 nmi is provided if communication relays or satellite data-

links are used. Most UAVs feature hybrid navigation systems (INS + GPS) and wheeled

takeoff and landing. Beside fixed wing vehicles UAVs with vertical takeoff and landing

capability (VTOL) are also available. The endurance and range of these UAVs are much

lower.

Representative UAV of Class 3 (above 2000 kg)

This class covers the high altitude long endurance (HALE) and combat UAV which require

higher payload capacities (Table A4). The satellite communication systems allow ranges of

greater 500 nmi. The UAV are typically driven by turboprop or turbofan engines.

The first military combat UAV (UCAV) are in the demonstrator phase, today. These are the

Boeing X-45 and the Northrop Grumman X-47 (Pegasus) which will be ship based. The

UCAV are the only UAV that carry explosive weapons.



Date: 10.12.01

3.3.1 Illustration of the UAV Categorisation

Appendix A provides a visualisation of the spread of main design parameters (e.g. mass,

airspeed, etc.) versus the maximum Take-Off Weight for different UAVs. Figure A1 to Figure

A4 provide a visualisation of such data which were selected from Table A1 to A4.

In Figure 3-1 the selected UAV are shown in an altitude versus takeoff mass diagram. It is

demonstrated that at higher altitudes the UAV are bigger and heavier. This is because the

payload size and weight increases with altitude due to the necessary longer range of the

payload, e.g. sensors and effectors. Furthermore, the UAV range and endurance increase,

too.

The scientific UAVs “Altus” and “Perseus B” are smaller although operating at high altitudes

as they are equipped with much smaller/lighter payloads.

In Figure 3-2 the UAV classes are correlated with altitude and flight velocity. It can be seen

that the speed is primarily a function of the type of propulsion system. With piston engines

driving a propeller (pusher or tractor) the preferred speed range is 150 kts. The turboprop

engines providing higher power than piston engines allow flight velocities up to 300 kts.

Above 300 kts turbofan engines are required. In this speed range (300 to 400 kts) counter-

rotating turboprops or prop-fans would further increase the endurance or allow smaller

platforms, but these engines are not off-the-shelf available, today.

The UCAV are carrying higher payload (weapons) than the reconnaissance and mission

support UAV and operating at higher speeds to increase the survivability.



Date: 10.12.01page 25

Figure 3-1 - UAV classes shown in an altitude versus takeoff mass diagram

Altitude versus max Takeoff Weight (Fixed Wing)

0

10000

20000

30000

40000

50000

60000

70000

1 10 100 1000 10000 100000

Takeoff Mass [kg]

Alti

tude

[ft

]

Class 1 (25 - 500 kg)

Class 2 (501 - 2000 kg)

Class 3 (above 2000 kg)

Class 0 (below 25 kg)

UAV for scientific

missions with small payload

Class 0 Class 1

Class 2

Class 3



Date: 10.12.01page 26

Altitude Versus max Speed (Fixed Wing)

0

10000

20000

30000

40000

50000

60000

70000

0 100 200 300 400 500 600 700

Max. Flight Velocity [kts]

Alt

itu

de

[ft]

Class 1 (25 - 500 kg)

Class 2 (501 - 2000 kg)

Class 3 (above 2000 kg)

Class 0 (below 25 kg)

Class 3Turboprop

Class 3Turbofan

Class 1+2piston/rotary eng.without turbocharger

Class 2piston/rotary eng.with turbocharger

Class 0piston eng.or electric

Primarily mil UAV(Class 2+3)Turbofan

HALE

LO HALE

MALE

UAV for scientific missions with small payload

Figure 3-2 - Correlation of the UAV classes with altitude and flight velocity



Date: 10.12.01page 27

3.4 Operation Control

A precondition for the safe integration of an UAV into air traffic management is the reliable

and secure operation control. This includes all technical devices which enable a bi-directional

data exchange between the UAV and corresponding operation control authorities. The data

exchange normally is separated in data which addresses operation related data and data

which describes ATC-related information. Normally, for integrity reasons, different technical

devices are used for the transmission of these two different data. For most applications this

twofold-approach for the data/communication link to a UAV offers a possibility for higher

redundancy in case of technical failures or damage of the ATC-related data-exchange

devices.

3.4.1 Air Traffic Control (ATC)

To maintain a safe, orderly and smooth air traffic, which also takes care of economic

aspects, each European state has established an air traffic provider.

The functions of these Air Traffic Service (ATS) providers include above all Air Traffic Control

(ATC) as well as acceptance, processing and forwarding of flight plans. Furthermore the

providers are responsible for planning, installation and maintenance of all technical systems,

required to fulfil these functions and of the navigation facilities for the airspace users.

Air Traffic Control comprises all phases of flight including ground operations in almost all

parts of airspace.

Flying in the civil managed airspace requires in the most cases the establishment of a

continuous two way communication via radio and/or data link (in the future), to perform all

interactive tasks between ATC and the responsible UAV operator, as between ATC and the

crew of manned aircraft.

These tasks comprise requesting and delivery of clearances, the advises necessary to

maintain the separation and especially the handling of emergencies.

3.4.2 UAV Control Stations (UCS)

The UAV control stations have to cover the following tasks:

• Mission planning

• Vehicle control during taxi, takeoff, approach and landing

• Vehicle control and guidance during flight

• Sensor control and payload/sensor data processing, display and exploitation



Date: 10.12.01page 28

• Image distribution to users

• Communication with operators and Air Traffic Control (ATC)

The number of tasks and levels of interaction depend on the type of UAV and the missions to

be performed. They can be categorised as follows:

Figure 3-3 - UAV Control Station Levels of Interaction

For long range systems, the UAV might be controlled by two or more UCS , e.g. one for

launch and recovery at the home-airport and another one, which may be far away from the

home-airport and the area where the UAV is accomplishing his task.

Beside ground based UCS, the UCS can be sea or air based, depending on the operational

requirements.

Air Vehicle / Sensor

No link tothe UAV

Only DataReceipt

DataReceipt

PayloadControl

DataReceipt

PayloadControl

FlightControl

DataReceipt

PayloadControl

FlightControl

Launch &Recovery

Level I Level II Level III Level IV Level V

UCS Levels of Interaction



Date: 10.12.01page 29

Figure 3-4 - Beyond line-of-sight operation with a HALE UAV using a remote airport (operating base)

Figure 3-5 - UAV Control Station (typical)

3.4.3 Data Link

The types of UAV data links and their requirements highly depend on the objectives of the

intended operation. The main characteristics are the operational range and the flight/mission

control capabilities as well as high availability and robustness of the data link.



Date: 10.12.01page 30

Currently the UAV use three types of data-link established between the UAV and the UAV

control station:

• flight and task control data-link

• system monitoring data-link

• task data-link

as shown in the following Figure 3-6:

Figure 3-6 - Data Links between UAV and UCS (scheme)

For flights of UAV in a commonly used airspace data links between UAV and ATC have to be

established. For airborne conflict detection and solution between UAV and other air traffic,

either manned or unmanned, a data link has to be established, for example ADS-B which is

planned to be established within the next years. The possible scenario is shown in the

following figure including the stated links:

• Data link between UAV and UAV Control Station (UCS). This link is mainly used fortask related data and direct UAV control.

• Data link between UAV and Air Traffic Control (ATC). This link is mainly used for AirTraffic Control, which means for example provision of separation including clearancesand spacing manoeuvres.

DATA LINKOperational Range (Distance)

Performance and QualityProtection of Link and Data

FLIGHT ANDTASK

CONTROLDATA

SYSTEMMONITORING

DATA

TASK DATA

UAV UCS



Date: 10.12.01page 31

• Data link between airborne vehicles. This link, possible ADS-B, could be establishedprimarily between all “mobile” participants in air traffic to provide data exchangeneeded for conflict detection and collision avoidance.

• Additionally a data link between entities like ATC and UCS could be established. Thislinks could provide direct access to the UAV-operator and serve as a backup forenhanced safety.

Air TrafficControl

Ground COM

Satellite

UAV

LowAltitude

UAV

UAV ControlStation (UCS)

Remote UCS

ADS-B

MannedAircraft

GroundCOM

Figure 3-7 - Data-and communication links (schematic overview)

Safety requirements for data links

The criticality of airborne vehicle operation requires a sufficient level of safety. This is

especially true for operation of UAVs which are controlled and accessed by data link.

Therefore the data link has to be designed to the following qualities:

• Safety

• Security and integrity (data protection)

• Availability and robustness (link protection)

Investigation into these subjects is of general benefit for civil air traffic and especially in times

of increased security needs due to terrorism threat.



Date: 10.12.01page 32

In the following Table 3-2 an overview on data links of selected UAV is presented. For details

on data links and data links of UAV, already implemented or planned, see Appendix C.

Name Manufacturer Nation Data Link UAV-Class

Mücke EADS Germany HF 1

KZO(Brevel)

STN ATLAS(Eurodrone)

Germany(FR/GE)

LOS (Ku)(C2 & video)

1

Phoenix GEC-MarconiAvionics

UK LOS (J)(C2 & video)

1

Pioneer Pioneer UAV(AAI/IAI)

USA LOS (C+UHF)(C2 & video)

1

Ranger Orlikon-Contraves

Switzer-land

LOS (UHF+MW)(C2 & video)

1

CL 289 EADS DornierCanadairSAT

GermanyCanadaFrance

only video (IR) down-link(LOS)

1

Mirach 150 Meteor CAE Italy LOS(C2 & video)

1

SperwerHV(high velocity)

SAGEM France LOS (Ku)(C2 & video)

1

Eagle-Eye Bell Helicopter USA LOS (C+UHF) dual up (C2) &single down

2

Seamos EADS Dornier Germany LOS (C2 & video)Ku 1-10 Mbps, UHF 10 Kbps),BLOS (C2) HF 1Kbps

2

GlobalHawk(Tier II plus)

NorthropGrumman(Teledyne RyanAeronautical)

USA LOS (X-band + UHF)SATCOM (Ku+UHF)(all C2 & video)

3

Predator B GeneralAtmoics

USA LOS (C-band,)SATCOM (Ku+UHF)(C2 & video)

3

GE UCAV EADS Germany LOS (X-/Ku-band, UHF),SATCOM (Ku+UHF), HF(BLOS)

3

Table 3-2 - UAV Selected for Analysis of Data Link (Overview)



Date: 10.12.01page 33

3.4.4 Navigation System

There is different navigation equipment aboard the UAV. The commonly used source for

position finding is Global Positioning System (GPS). Details of navigation systems of specific

UAVs are described in the according tables.

3.4.5 Flight Management System

The Flight Management System (FMS) used in manned aircraft contains databases for all

way-points and navigation aids in the respective area. The planned route of a particular flight

is entered before commencement of the flight, updates are possible at any time. Further the

FMS keeps track of all relevant data concerning a particular flight, for example fuel data. For

autonomously operating UAV a similar system has to be realised and accessible for the UAV

controller.

Having access to the flight management system has to be part of requirements for UAV; this

should be discussed in more detail in the follow-up study.

3.4.6 Other Relevant Equipment

Integration of UAVs into ATM could lead to a requirement for carrying TCAS, Collision

Warning System or Transponder. For details on collision warning equipment refer to

Appendix E – Collision Avoidance.

3.5 Consideration of Achievable Flight Path Accuracy

Considerations of achievable flight path accuracy are beyond the scope of the preliminary

study. This should be accomplished, on the basis of the UAV data available, in the follow-up

study.

However, to give already some guidance for the follow-up study in the following chapter a

preliminary classification scheme is provided.

3.5.1 Preliminary Classification Scheme for Accuracy of Trajectory

For a better handling the achievable flight path accuracy should be categorised and put into

an appropriate classification scheme. A possible and preliminary scheme could contain

• Accuracy categoryThis is the category identifying the achievable accuracy.

• Grade of deviation from planned / required flight pathThis row contains the description of the grade of deviation from flight path. Deviation inthis context means lateral and/or vertical deviation with respect to time.



Date: 10.12.01page 34

• Explanation / DefinitionThe grade of horizontal deviation in feet or lateral deviation in nautical miles and thetime margin for recovery. If either term is exceeded the deviation will be transferred intothe next category.

A preliminary classification scheme is shown below, it should be stressed, that it should be

refined or even adapted during the follow-up study if necessary.

AccuracyCategory

Grade of Deviation fromPlanned / Required Flight Path

Explanation / Definition

I No Deviations -

II Minor Deviations Deviations in altitude of not morethan 100 feet. Lateral deviations of

not more than a nautical mile.

UAV is able to correct deviationwithin 10 seconds.

III Remarkable / ConsiderableDeviations

Deviations in altitude of not morethan 500 feet. Lateral deviations ofnot more than one nautical miles.

UAV is able to correct deviationwithin 30 seconds.

IV Extreme Deviations Deviations in altitude of more than500 feet. Lateral deviations ofmore than one nautical miles.

UAV is not able to correctdeviation within 30 seconds.

Table 3-3 - Preliminary Classification Scheme for Flight Path Deviation

3.6 Preliminary Assessment of Failure Modes

3.6.1 General Description of the Failure Mode Table

In this chapter the general approach for the assessment of the failure modes is presented. A

detailed assessment will be part of the follow-up study; however, some failure modes were

already described preliminary and entered in the table for failure modes. The exemplary table

is attached to this report in Appendix H.

The table for the failure modes includes the following items, for details see Figure 3-8:

• FunctionThe area of functionality, the description of the areas is given below.



Date: 10.12.01page 35

• Failure modeThe failure mode to be regarded.

• Flight phaseThe phase of flight for the occurrence of the failure; the description of the phases isgiven below.

• Operational consequencesThe operational consequences of the respective failure mode is described.

• Hazard descriptionThe hazard resulting, or possibly resulting from the respective failure mode isdescribed. Emphasis is given to ATM related hazards.

• Severity categoryThe severity of the hazard resulting from a failure mode, if there is more than onehazard, the most severe hazard will be given. The description of the severitycategorisation is given below.

For the completion of the Failure Mode Table, workshops with experts from all relevant

sectors and experiences, for example Air Traffic controllers, UAV operators and system

engineers should be used. The structure of the table is shown in the following Figure, the

table with exemplary failure modes inserted preliminary is attached in Appendix H.

Figure 3-8 - Structure of Failure Mode Table

3.6.2 Function Areas for Failure Mode Assessment

Presently there are six basic function areas identified which are listed below:

• Engine powerThis area covers all engine problems, i.e. total loss of engine power and partial loss ofengine power in different phases of flight.

• ATC data linkThis area covers the data link between ATC and the UAV including possibly existing

FUNCTION FLIGHTPHASE

FAILUREMODE

OPERATIONALCONSEQUENCES

HAZARD DESCRIPTION(ATM-VIEW)

SEVERITYCATEGORY



Date: 10.12.01page 36

voice communications between ATC and the UAV controller. All ATM related data areexchanged via the ATC data link.

• UAV control data linkThis area covers the data link which is established between the UAV and the UAVcontrol station. It is used for all control purposes and control-related data.

• ControllabilityThis area covers all airborne UAV control functions, either mechanically orelectronically. For example all control surfaces, possibly existing hydraulic systems,flight control system including computers and further more.

• Navigation / AvionicsThis area covers all devices used for navigation purposes as well as all devices usedfor maintenance of either 4-dimensional trajectory or separation purposes. Thisincludes for example Air Data Computers (ADC), Radar Altimeter (RA) and especiallyall sense and avoid devices.

• MiscellaneousThis area covers all functions which are not covered by the areas mentioned above.This could include items as for example payload or mission related equipment as wellas fuel status, onboard self testing and failure identification etc.

3.6.3 Phases of Flight

For the further proceeding the following phases of flight are foreseen to be regarded for the

identified failure modes:

• Flight PlanningThis phase includes all activities for the flight preparation, for example the routeplanning, fuel calculation or filing of flight plans.

• Ground movementThis phase includes the movements between the gate, or a comparable position, andthe runway (taxi).

• Take offThis phase starts with commencement of take off roll and ends at 1500 feet aboveground. For UAV there are several take off modes identified:

- Normal Take-Off

- Vertical Take-Off

- Rocket-boosted Take-Off

- Air-Drop from Carrier-A/C

• Departure and climbThis phase starts at 1500 feet above ground and ends when the UAV reaches itscruising altitude. The departure may be flown using omni-directional departure orStandard Departure Routes (SID).

• CruiseThis phase starts when the UAV is reaching cruising altitude and ends with thecommencement of descent for approach and landing. This phase especially includesthe portion of the flight, of any duration, which could be called the “core intention” (inmilitary terms the mission), and is the purpose of the flight.



Date: 10.12.01page 37

• Special Operation / mil. Missions incl. leaving & re-entering the Air-Route Systemand/or the civil managed AirspaceThis phase may be either applicable to some military UAV missions which normallyhave to leave/re-enter the civil managed airspace if the area of military operation isreached/left; even more this special operation phase is dedicated to such UAV whichhave to leave/re-enter the air-route system (but not the civil managed airspace) if theflight task (e. g. surveillance, mapping, airborne Telecommunication relay-station, etc.)requires a departure from other ATM regulations (e.g. air-route System).

• Descent and arrivalThis phase starts with commencement of descent at the end of the flight and ends atthe Initial Approach Fix (IAF), or an appropriate point. This might include radar vectors,transition routes or Standard Arrival Routes (STAR).

• Approach and landingThis phase starts at the IAF and ends with the vacation of the runway. For UAV thereare several landing modes identified:

- Normal Landing

- Vertical Landing

- Parachute Landing

- Docking at airborne Host A/C

3.6.4 Modes of Operation

Basically this document divides the operations of UAV in three modes of operation, which

are:

• Normal operations; they include

- Ground operations,

- In-flight operations with all systems working normal,

- Communication operations.

• Abnormal operations; they include

- Degraded system function,

- Failure of redundant systems,

- Adverse weather conditions (e.g. icing conditions).

• Emergency operations; they include

- Lack of redundant systems after failure of systems (including degraded or failedelectrical sources),

- System function degraded to an extent that disables the UAV to keep itstrajectory within specified limits (also partially),

- Loss of communication

- Loss of data link



Date: 10.12.01page 38

3.6.5 Severity Categorisation

For the severity of the hazards for operational consequences resulting from certain failure

modes the severity classification used in Eurocontrol is choosen and listed in Table 3-4

below. For details see Eurocontrol Safety Regulations Requirements (ESARR) 4 – Risk

Management and Mitigation, Appendix A.



Date: 10.12.01page 39

Severity

Category

Effect on

operations

Examples of effects on operations

1 Accidents • One or more catastrophic accidents,• One or more mid-air collisions• One or more collisions on the ground between• Two aircraft• One or more Controlled Flight Into Terrain (CFIT)• Total loss of flight control.

No independent source of recovery mechanism, such assurveillance or ATC and/or flight crew procedures canreasonably be expected to prevent the accident(s).

2 Serious

incidents

• Large reduction in separation (e.g., a separation of lessthan half the separation minima), without crew or ATCfully controlling the situation or able to recover from thesituation.

• One or more aircraft deviating from their intendedclearance, so that abrupt manoeuvre is required toavoid collision with another aircraft or with terrain (orwhen an avoidance action would be appropriate).

3 Major

incidents

• Large reduction in separation (e.g., a separation of lessthan half the separation minima), without crew or ATCfully controlling the situation or able to recover from thesituation.

• minor reduction (e.g., a separation of more than halfthe separation minima) in separation without crew orATC fully controlling the situation, hence jeopardisingthe ability to recover from the situation (without the useof collision or terrain avoidance manoeuvres).

4 Significant

incidents

• increasing workload of the air traffic controller or aircraftflight crew, or slightly degrading the functional capabilityof the enabling CNS system.

• minor reduction (e.g., a separation of more than halfthe separation minima) in separation with crew or ATCcontrolling the situation and fully able to recover fromthe situation.

5 No immediate

effect on

safety

No hazardous condition i.e. no immediate direct or indirect

impact on the operations.

Table 3-4- Severity Classification for Hazards (acc. ESSAR 4)



Date: 10.12.01page 40

4 Impact of UAV Operations on ATM

This chapter addresses potential implications and impacts of UAV-Operations on ATM-

related procedures and regulations. As such, current ATM-Regulations and –Procedures

were described in the Appendix D, E, F, I so far they are needed for further understanding.

This ATM framework of current regulations and procedures is assumed to provide an

operational environment for this initial analysis of potential implications resulting from UAV

operations.

Initially a check of all implications during all states of normal UAV operations has to be

performed, which are:

• Flight planning

• Ground Control

• Take-Off

• Cruise

• Special Operation in and outside of the IFR air route system / mil. Missions incl. leavingand re-entering civil managed airspace

• Cruise

• Approach

• Landing

Special UAV procedures have to be considered for:

• Take-Off Procedures

- Normal Take-Off

- Vertical Take-Off

- Rocket-boosted Take-Off

- Air-Drop from Carrier-A/C

• Landing Procedures

- Normal Landing

- Vertical Landing

- Parachute Landing

- Docking at airborne Host A/C



Date: 10.12.01page 41

4.1.1 UAV Flights within Controlled Airspace

Initially operations within the controlled airspace depend on applied flight rules (IFR or VFR)

and as such on the weather conditions (IMC or VMC) as well. Flying in VMC implies that

airspace observation, or the „see and avoid“ principle is performed at a certain extent,

regardless if the flight is conducted under IFR or VFR. For that reason the following will be

spread into IMC- and VMC-related considerations.

4.1.1.1 General Considerations for UAV Flights within Controlled Airspace in IMC

UAV operations in IMC require flight under IFR, which is assumed for UAVs to be the regular

condition of operation.

UAV, which are guided by a UCS should take part in the full suite of data exchange and flight

information services which are offered by ATC as mentioned in Appendix D. Thus UAV which

fulfil equipment and redundancy requirements (e. g. transponder, redundant data exchange

channels, etc.) can take part in IFR traffic under IMC.

The level of UAV authorisation and airspace access will be selected by the ATC Controller at

hands of the known UAV level of autonomy and the manouvrability of the UAV. As such a

sufficient level of information about these crucial UAV parameter needs to be provided for the

ATC controller. This data should be made also available by an automatic distribution via

transponder or ADS-B in the future.

On the other hand for support of the UAV design process an acceptable minimum level of

autounomy and manouvrability has to be defined in order to establish UAV certification

criteria and requirements. These regulatives have to be met by each UAV for maintaining

safe and efficient traffic flow.

4.1.1.2 General Considerations for UAV Flights within Controlled Air Space in VMC

In the near future UAV flights will not be classified as VFR flights, but UAV operations will

also be conducted in an airspace, where VFR flights of manned aircraft are possible. General

regulations for flights in IMC are provided in Appendix D. In order to give appropriate

flexibility to UAV operation, one of the long term goals of UAV integration into civil airspace

should be as follows.

• Beside using IFR air route sytems a UAV must also be able to leave the IFR air route

system for special operations which have to be performed in the controlled airspace.



Date: 10.12.01page 42

• Such an UAV will operate in the controlled airspace in a similar manner as VFR traffic in

the controlled airspace.

• Hence the UAV does not rely on optical visibility (“see and avoid”) like a human air crew

but on a sophisticated sensor suite (“sense and avoid”), the UAV is not restricted to VMC,

but can operate in IMC as well.

Equipped with available sensors and detection measures, the UAV-onboard available traffic

information can resolve the problem of sensing other traffic participants. Details on sensor

suite, control of current UAVs by the operator and additional topics are described below and

in the appendices.

In case the UAV receives collision warnings either by ATC or onboard equipment, some

prompt reaction, e. g. change of the flight path, is necessary in many cases.

The ability of the UAV to follow such collision warnings depends basically on the level of

manoeuvrability of the vehicle. Beneath that there are other parameter to be taken into

account:

• The concept of the Flight Control System (FCS),

• The level of autonomy of the UAV,

• The situational awareness of the UCS operator,

• The feasibility of prompt manoeuver inputs by the Man-Machine-Interface (MMI) of the

UCS.

In order to perform evasive manoeuvres for collision avoidance a minimum design

requirement shall be developed and defined by means of time for initiating a certain reaction

of the UAV. This has to be integrated into design requirements for UAVs and UCS as well.

In order to develop design requirements for such events, normally the possible worst case

scenario becomes design diver character. One of such worst case situations for flying VFR

within a controlled airspace is as follows:

VFR air traffic has no traffic information available, transponder is not switched appropriately

due to disregarding the rules and VFR-rules are not followed (flying in clouds or neglecting

the distances from clouds).

Thus, the respective VFR air traffic is not known to ATC. On the other hand, the VFR traffic

has no traffic information by ATC, has no TCAS/ACAS advisories and itself is hampered

partly from using own “see and avoid” strategy due to insufficient visibility of the irregular

VFR traffic. An UAV, flying in the controlled airspace according to IFR or similar as VFR



Date: 10.12.01page 43

traffic on a sense and avoid basis, has to detect this worst case traffic and avoid it.

It may be forwarded to some further workshop discussions if such a criteria should be

established. It is the intention of this preliminary study only to indentify areas of implications

to other air traffic which result from out of UAV operations.

Problems of mixed IFR and VFR traffic are discussed in the following chapter.

4.1.1.3 Special Considerations for UAV Flights within Controlled Airspace

UAV operations within the controlled airspace are for further considerations separated into

the following parts:

• (a) Operation in the Terminal Control Area (TMA),

• (b) Operation En-route,

• (c) Operation in high Altitude

The Terminal Control Area is the controlled airspace, within which aircraft can take off from

an airport and climb the first portion of their en-route altitude (to be co-ordinated into the en-

route traffic flow) completely under control by the appropriate ATC units. To a large extent,

parts of this area offer to the UAV the possibility to climb without encountering uncontrolled

traffic under VFR to flight levels, where generally no unknown air traffic exists.

The en-route portion of controlled airspace is divided into lower and upper controlled

airspace, with a separation level of FL 245 respectively FL 290 already or at least in the near

future in for the European airspace.

(a) UAV Operation in the Terminal Area

The terminal area portion is composed of controlled airspace with additional restrictions for

VFR traffic (entry of Classes C and D, control areas and CVFR areas only with clearance by

ATC) and normal controlled airspace, which may be entered by VFR traffic under the

appropriate VMC. Generally terminal areas in countries or parts of countries with high airport

density tend to form one single, sectored area. Around an airport / several airports with high

traffic rates, the terminal area suffers from congestion, aggravated by the fact, that aircraft

have to fly special routes for noise abatement. It must be avoided, that UAV operation could

hamper the envisaged increase in overall traffic capacity and reduction of delay and cost.

Operation and integration of UAV in these areas is problematic, especially if these UAV have

to use the same infrastructure as manned vehicles, i.e. apron, taxiways, runways, and in



Date: 10.12.01page 44

case lack of direct communication in connection with limited direct situational awareness of

the UAV operator (presumed no direct eyesight of the UAV to be controlled). Consequently,

expeditious behaviour, often requested by ATC, requires safe communication to and from the

UAV to avoid high risk. STOL UAV or launched UAV may operate without contributing too

much to congestion, provided appropriate landing area is given as needed, and no conflict is

generated with manned STOL vehicles.

Many civil applications of UAV, probably of the smaller classes, may take place within the

terminal areas or lower controlled airspace. Thus problems arise, because in these parts of

airspace “sense and avoid” strategy must be used in addition to ATM procedures performed

by ATC. This in turn means various pieces of sensing equipment in addition to payload and

ATM related equipment impact the economy of UAV-operation in this part of airspace.

Within the chapter 4.2.2 separation safety, respectively the corresponding Appendix F, the

aspects of procedure design, separation assurance and sequencing, especially for the

terminal area are briefly discussed.

(b) UAV Operation En-route

In the lower as well as in the upper controlled airspace all sorts of air traffic, flying under IFR

and under control of ATC, take place. Depending on the purpose of the operation, future

operation of UAV may be planned in all altitudes.

Within controlled airspace, the centres of air traffic are connected with air routes, in former

times dependent on ground based navigational aids, with upcoming Area Navigation (B-

RNAV and P-RNAV) independent from ground based facilities.

UAV going en-route must be co-ordinated into the en-route traffic, within en-route traffic and

out of the en-route traffic as well. So, UAV are flying basically under the same conditions as

manned aircrafts under IFR.

To reach the lower or upper controlled airspace, the UAV has to climb either within controlled

airspace or to climb within uncontrolled airspace until controlled airspace is reached. In both

cases, the UAV has to cope with traffic under VFR (confer type of airspace above). In

controlled airspace and IMC, in airspace where traffic under VFR is controlled to a certain

extent and generally above FL 100, no unknown and uncontrolled VFR traffic will be

encountered. To avoid unknown and uncontrolled air traffic flying under VFR and all other air

traffic, many, if not all UAV operation, rely on flying under IFR and only in airspace, where

VFR traffic is under control. Though appropriate sensing techniques are technical feasible,

there is a lack of simultaneous low price and lightweight equipment at present, thus inhibiting



Date: 10.12.01page 45

true autonomous and safe collision avoidance, needed for usage of “mixed” airspace.

However, this will change in the future.

The UAV operation in civil airspace requires the UAV to be kept in at least the same

separation from other traffic as manned aircraft among themselves. In addition, in various

papers many possibilities are discussed, to impose restrictions to UAV in order to assure this

separation or generate a higher degree of separation. Research concerning separation

safety (and sequencing if applicable) is needed.

(c) UAV Operation in High Altitude

Some UAV with HALE - capability are operating in FL 600+ well above the normal cruising

levels of long range air transport (FL 300 to 450) and even SST Concorde (FL 510). An UAV

record was set in 2001 up to FL 965, an altitude held for about 40 minutes (this vehicle is not

planned for integration into unreserved airspace). This operation is taking place above the

established air route system, so that the UAV is not flying IFR in this portion of the flight.

In case of any time critical emergency or during normal descent, the UAV has to be co-

ordinated through all the different categories of airspace down to the (emergency) landing

site.

4.1.2 UAV Flights within Uncontrolled Airspace

4.1.2.1 UAV Flights in Uncontrolled Airspace

The Appendix D briefly describes some of the regulations for flying in an uncontrolled

airspace. Since IFR flight are prohibited within this airspace, UAV operations in uncontrolled

airspace which is commonly used by other traffic, are not expected for the near future. So the

following brief considerations are preliminary only.

The UAV, flying in uncontrolled airspace, must have at least adequate “sense and avoid”

possibility, with a Human Machine Interface (HMI) adequate for the special situation of the

remotely piloted vehicle. For an autonomous flight (Appendix J), all separation related

functions must be fully automated.

Flights of UAV in uncontrolled airspace are not relevant for ATC, however, many concerns

with respect to ATM exist:

• UAV may fly from controlled into uncontrolled airspace, under ATM control or militarycontrol, and vice versa. Therefore the UAV have to be released from or co-ordinatedand cleared into controlled airspace.



Date: 10.12.01page 46

• UAV flying in uncontrolled airspace may unintentionally enter controlled airspace, byerror or in case of emergency, when climbing, descending or laterally deviating. Thismay pose a more serious threat than a manned aircraft, entering controlled airspaceunintentionally, because ATC has less possibility to address to the UAV. However,measures can be taken for remedy, for example:

- All operators of UAV have to listen to ATC emergency frequency calls receivedby UAV

- All operators have to file a UAV-flight plan for any flight

- All operators have to switch transponder

4.1.3 UAV Operations within Special Use Airspace

General regulations concerning the Special Use Airspace (SUA) are briefly introduced in

Appendix D.

UAVs may be participating elements within a Special Use Airspace, as well as transitioning

elements. Normally the special operation flight phase which may be closely dedicated to the

UAV flight task may be mainly performed within a SUA.

Furthermore, take off and landing or launch and recovery of a UAV may take place within

any kind of SUA, whereas the purpose of the flight is fulfilled elsewhere. So the procedures

for leaving and re-entering a SUA will have implications on other en-route traffic. Especially

the re-entering of a SUA requires adequate separation distances to be provided by ATC. As

such adequate procedures for such utilisation of airspace by UAVs must be established.

Special Use Airspace must be taken into account during flight planning.

4.2 Provision of Separation and Collision Avoidance

4.2.1 Basic Regulations for Separation and Collision Avoidance

Basically the separation of traffic conducted under different flight rules is depending on the

flight rules and the used airspace. The following Table 4-1 gives an overview of normal

means for maintaining separation and therefore assuring collision avoidance.

UAV operating in the commonly used airspace have to comply with these regulations

presently. However, further investigation and development may indicate alternative means or

regulations for the above mentioned purposes.



Date: 10.12.01page 47

Flight Rules

Air Space

Separation between

VFR and VFR traffic

Separation between

IFR and VFR traffic

Separation between

IFR and IFR traffic

uncontrolled See and avoid

TCAS *)

See and avoid

(at boundary) Not applicable

controlled in IMC Not allowed

Radar Separation

TCAS *)

See and avoid

(if possible)

Radar Separation

TCAS *)

ADS-B *)

See and avoid

(if possible)

controlled in VMC

See and avoid

TCAS *)

Radar Separation

TCAS *)

See and avoid

(if possible)

Radar Separation

TCAS *)

ADS-B *)

Special use Airspace See and avoid

(if possible)

TCAS *)

Radar Separation

TCAS *)

See and avoid (if possible)

*) 3-dimensional if available when ADS-B equipped

Table 4-1 - Separation Means Depending on Flight Rules and Airspace

4.2.2 Separation Safety

(Factors Potentially Affecting Separation Safety and Application to an UAV Operation)

In reference [20]: “A Concept Paper For Separation Safety Modelling”, subtitled “An FAA

Eurocontrol Co-operative Effort on Air Traffic Modelling for Separation Standards”, a

comprehensive list of respective factors, affecting separation safety, can be found.

These factors are valid for all kinds of separation provided by ATC (e.g. IFR from IFR and

IFR from VFR). They are also valid during ATM emergency procedures. The factors are

furthermore valid for UAV, at least to various extents. In addition, these factors give a hint for

the operation of UAV outside the published air route system for flying IFR. Flights of the latter

type are very likely to be performed by civil UAV, fulfilling a special flight purpose in the

managed airspace.



Date: 10.12.01page 48

Interactions among these factors must also be considered, as must be the possibility that

external factors, e.g. emergencies, might impact more than one of the primary safety-related

factors.

In this chapter an overview of the factors, affecting separation safety, is given and the factors

are discussed with respect to UAV operation briefly. The structure of [20] is maintained

throughout the discussion in order to enhance cross reference to the original document [20].

• “Chapter A” - Relative aircraft positions and velocities (encounter geometry)

- “Sub 1” - Blind-flying riskThis risk comprises factors that affect risk without any intervention. With respectto UAV, this risk is related to the UAV vehicle, its seize and its performance.

- “Sub 2” - Pilot intervention – factors that affect timely pilot detection andcorrectionThis risk comprises all factors, connected with the timely pilot detection of another (intruder) aircraft on collision course or loss of separation by visualperception, “party line” effect. Furthermore, factors as reliance on ground basedsurveillance, workload or TCAS limitations. With respect to UAV, these factorsare discussed, especially “see and avoid” and “sense and avoid”

- “Sub 3” - ATC intervention – factors that affect the probability of timely andeffective ATC interventionThese factors comprise the possibility of ATC intervention with respect to UAV.One fact is, that the average traffic diversity a controller has to cope with mayincrease with spreading UAV operation.

- “Sub 4” - Aircraft reaction – factors that affect aircraft reaction time in response toa needed manoeuvreThe reaction time of an UAV to an advise by ATC may differ significantly fromthat of a manned Airline transport by several reasons, which are discussed indetail in the appendix F.

• “Chapter B” - ATC rules and procedures, airspace structureCivil UAV have to use civil managed airspace and have to be adapted to the existingrules and procedures as far as possible. Some are discussed in detail in the appendixF, e.g. filing of a flight plan or procedure design.

• “Chapter C” - Communication capabilityThe main difference between manned and unmanned vehicles is the fact, that in thelatter no direct voice communication between ATC and the crew on board can takeplace. All communication is via link between ATC and UCS or, in case of fullyautonomous flight of UAV, between ATC and a component of Artificial Intelligence onboard the UAV. (Refer to the appendix J - Autonomous Flight)

• “Chapter D” - AircraftAll vehicle aspects are mentioned, from certification and maintenance to vehiclesystems and equipment. A detailed discussion is given in the Appendix F with respectto TCAS. Refer also to the appendix E - Collision Avoidance”.

• “Chapter E” - Ground/Satellite systems: Surveillance and NavigationAs far as the equipment of an airline transport is also installed in an UAV, the samefactors are valid for both vehicles. However, in case of UAV special attention must begiven to spoofing, jamming and other undesired external interference.



Date: 10.12.01page 49

• “Chapter F” - Human performanceIn case of an UAV, human performance refers mainly to the MMI of the UCS.

In the respective Appendix F , a complete listing of the factors, together with a detailed

discussion, concerning UAV operation, can be found. The structure of the reference paper

[20] is maintained, to ease the allocations and search in the reference document.

The previous criteria for separation safety are valid for en-route flight and also for climb and

descent to / from en-route altitude within the TMA.

4.3 Procedures for UAV Hand-Over and Border Crossing

Due to various problems to be solved for integration into the air traffic, it is likely, that the first

UAV taking part in civil air traffic in the general airspace will continue to take off and to land

not on an active civil airport with CTR but on separate sites. However, for some portion of the

flight, these UAV will use unreserved airspace, flying IFR, co-ordinated and separated by

ATC. Concerning the procedures for such transitions Appendix I provides initial information.

With respect to border crossing, UAV additional cooperations and according regulations have

to be defined between the Nations involved in that flight.

These regulations, beneath other issues, have to focus on the following items:

• Bi-lateral acceptance of the UAV as an air traffic participant,

• Commonly agreed ATM procedures for failure cases,

• Common acknowledgement of UAV airworthiness standards,

• Acceptance of common qualification standards for UAV control authorities and personnel,

• Definition of applicable data link technologies,

• Commonly agreed procedure for clearing of customs,

This enumeration could be arbitrary extended, and as such it does not claim for

completeness. Nevertheless, this brief note clearly indicates that border crossing operations

of UAVs never could be conducted if not a common understanding between Nations could be

settled, how to integrate UAVs into civil airspace. The achieving of this “common sense” is

the most important pre-condition in order to enlarge the application of civil UAVs to multi-

national operability.

To this innovative spirit the follow-on study of this preliminary study will be dedicated

essentially.



Date: 10.12.01page 50

4.4 Ground Operations

In the following chapter, some of the problems of ground operation of an UAV on a civil

airfield are outlined.

Ground operations in general adhere also to certain separation criteria. For this report

“ground operation” is understood as all movements from the parking position to the lift off and

from touch down to the parking position.

The most demanding case of ground operation on a civil airport is as follows:

• The UAV (wheel taxi capability in contrary to some V/TOL with skids only) is parkedand readied for T/O on a civil airport with totally mixed traffic (airline, general aviation,helicopters and ground vehicles).

• From the parking position, the UAV has to taxi along the system of taxi ways, includingcrossing of active runways to a “number one” position

• From the “number one” position, the UAV is cleared to enter runway, aligned for takeoff and beginning the take off run until lift off, followed by a climb out on SID or otherrouting.

Some relief is achieved for all following cases:

• The UAV taxis on special taxi ways, avoiding as much as possible the normal mannedground traffic.

• The UAV does not taxi by remote control but follows a manned ground vehicle byoptical and/or other coupling (not mechanical).This offers the advantage, that the equipment for ground operation can be minimised toequipment needed for the take off run (see below). Techniques for these procedure areavailable in ground vehicle research.

• The UAV is towed to the take-off position conventionally by a manned ground vehicle.

• The UAV has V/STOL capability or is launched. In both cases, especially the landingposes different additional problems with respect to integration into the all over trafficsystem of an airport.

All these procedures arise the following questions:

• Interface between the ground operation procedure and the transition to the take-off runand flight operation,

• take-off and flight guidance in terms of technical means and location of the UCS. (Itmay be that the UCS for the flight portion is not the same as the UCS for the groundoperation. The latter is favourably positioned on the airfield from where the take offtakes place, if possible with direct visibility to the UAV and with a surveillanceequipment exceeding today’s equipment (mainly radar). The ATC Unit/Ground Controlmust have immediate access to stop the UAV. All this can be embedded in anadvanced airport management tool.

Due to various significant problems for UAV ground operations which are currently even

technically unresolved, an adequate integration into the ground traffic of an airport seems not

feasible for the near future term. For that reason it is likely, that UAVs, taking part in civil air



Date: 10.12.01page 51

traffic in the general airspace will continue to take off and to land not on an active civil airport

but on separate sites. For take-off and landing, these UAV could use a reserved airspace,

and perform a transition into the controlled airspace for cruise and special operation, which

will be co-ordinated by ATC.

As in flight operations, also ground operation is divided into the guidance and control portion,

performed by a UCS and the independent surveillance function, performed by the respective

ATC unit (ground control), using the future advanced surface management tools, eventually

embedded in a total airport management system.

4.4.1 Guidance and control by the UCS

Finding the way on the ground can be achieved by a lot of techniques, known from

autonomous ground vehicle research. Like manned aircraft on airports too, the UAV will

follow a system of taxi ways along the centreline of these taxi ways.

On the taxi ways or on a system of lines on a wide apron, crossings can be marked

separately and appropriate actions taken automatically or at least triggered or warned

automatically and taken by the UCS, as priority ranking.

Techniques are induction devices in the tarmac, optical line tracking which allows automatic

tracking and simultaneously optical guidance and control limits to a ground operator for

surveillance and avoidance of deviation onto soft-ground, collision avoidance during ground

operation etc.

In addition to the guidance along special ways (lines) collisions must be avoided. Given that

the UAV does not deviate from the intended way other ground vehicles can collide into the

UAV or block the way of the UAV. As in manned vehicle operation, the UAV must be able to

detect these obstacles and stop automatically or at least show these obstacles to an

operator.

Various techniques for collision avoidance are also available from ground vehicle research.

Even if taxiing is done automatically, the operator of the UAV ground movements should

have a device to follow the movement of the UAV. This may be a moving map of the airport

or may be an enhanced or synthetic vision display.

4.4.2 Independent surveillance function, performed by ATC (Ground control)

In principle the requirements with respect to UAV do not differ from manned airport traffic.

The tasks are performed by the radar based Airport Surface Detection Equipment (ASDE).

But due to fact of unmanned operation, the accuracy of the surveillance must be enhanced.



Date: 10.12.01page 52

This is the case for manned operation too, to avoid the increasing number of (reported)

runway incursions.

In addition to improvements of special radar equipment, the following techniques are

envisaged, offering higher accuracy as well as update rate and other advantages, as stand

alone or complementary to Radar:

• ADS-B on basis of DGPS and local augmentation system to enhance accuracy.

• Multilateration (exploiting all sorts of transponder emissions).

4.5 Military Operations

Due to the vital role for European security, which is acknowledged by Eurocontrol in [22],

military aviation will continue to be a factor in airspace. Since military UAV gain technical

maturity and long range endurance as well as operational importance, they are likely to

become the first routine users of the unreserved airspace. This poses problems of integration

into the air space system as well as problems to cope with the wide range of military

concerns.

Like manned military aircraft, military UAV should be able to switch from compliance with civil

ATM requirements to compliance with military operational requirements and vice versa,

according to the airspace they use.

4.6 Flight Termination System (FTS)

Depending on the UAV level of autonomy, for smaller UAVs a flight termination system (FTS)

may be required for loss of control data link and other cases, in which the flight cannot be

terminated in a normal manner. This flight termination system must be able to terminate the

flight without endangering other air traffic or humans and property on the ground. Therefore,

for smaller UAVs a system on bases of a parachute, para-glider or Ragallo wing seem

suitable, depending on the UAV vehicle. The flight termination descent has to be co-

ordinated by ATC, if applicable, hence some steering of paragliding device is required as well

as capability to be surveilled (transponder, radar reflector etc).

The following questions need to be discussed further, mainly with respect to certification:

• Under which circumstances a FTS should be required ?

• Is a single System in combination with FTS equal to a redundant system?

• Requirements for FTS (non explosive, steerable, to be triggered via separate source,etc.)?



Date: 10.12.01page 53

5 Proposed ATM Requirements

5.1 ATM Requirements

A design guide for UAV procedures is beyond the scope of the pre-study; however, some

preliminary considerations with respect to UAV procedures will be given.

5.1.1 UAV operations in existing air route scheme (IFR)

As addressed above, the UAV must be able to follow the published procedures on the

respective routing and fulfil all the criteria concerning RNP of the navigation system on this

routing. The UAV must be able to be separated in vertical, longitudinal and lateral direction in

the same way as the manned aircraft in the same airspace. Nevertheless all ICAO rules of

the air and air traffic services must be reviewed with respect to UAV (e.g. adaptation /

cancellation of all visual manoeuvring).

The UAV must be certified with respect to all equipment.

If take off and/or landing are planned on a civil airport, the equipment of the UAV must be

compatible to the ground devices and facilities in order to obey to the established procedures

at an required level of flight path constraint. Alternatively the UAV may fly these procedures

with own equipment on board/on ground with the same required accuracy. In addition,

ground operation must be assured on runway(s), taxiways and apron. Separate procedures

for UAV may be foreseen, if the safe, orderly and economic flow of air traffic is not

endangered.

Ideally, the UAV acts and reacts in all phases of flight including ground operations identical to

a manned aircraft. This would minimise the effort for UAV integration into ATM since no new

procedures or requirement have to be addressed to ATM in that case.

Envisaged airspace categories (ICAO) are those for IFR traffic and which provide separation

of VFR from IFR. Categories A – C, require minor effort for integration. Rising effort is seen

for categories D – F, where IFR traffic is possible, but VFR traffic is not completely known or

able to be detected, (except CTR D). Thus VFR traffic cannot be separated. UAV must sense

and avoid this traffic by itself.

This operation concept must be confirmed by a safety case and tested to necessary extent.



Date: 10.12.01page 54

5.1.2 UAV operations outside existing air route scheme (off airways).

Such operability will be requested for UAVs in order to fulfil special task-related flight

operations. These may be, e.g.:

• Flying of special Patterns for Search and Rescue

• Flying of special Patterns for Environmental Surveillance / Pollution Detection,

• Coastal- / Border-Surveillance and Control,

• Flying of special Routes related to Surveillance of Infra-Structural Facilities (Pipelines,Airports, Railways, Roads, Waterways, Channels, High Tension Cables, etc.),

• Long endurance Holding Patterns for acting as a Airborne Telecommunication Relay-Station,

• Airborne Crime Reconnaissance,

• Conduction of military Operations embedded within ATM,

• Conduction of military Operations with leaving / entering an ATM Environment.

It is not claimed that this list is complete. It is understood as a basis for further investigation

into special UAV-related ATM/ATC – procedures which still have to be worked out.

To join the published IFR system, all conditions of 4.1.1 must be fulfilled. The UAV should

have the maximum surveillability by ATC, i.e. should be always known to ATC including as

much intent as possible (maximum intent is the so called “instantaneous intent”). This

requirement automatically projects forward into the Eurocontrol traffic environment model in

[22].

This operation concept must be confirmed by a safety case and tested to the necessary

extent.

5.1.3 UAV operations in uncontrolled air space.

Given the conditions of 4.1.1.and 4.1.2. the UAV has the maximum flexibility for performing

distinct flight purposes. Flying in F and G requires a complex effort concerning equipment,

discussed on various places in this report, especially the chapter concerning separation

safety. This equipment assures “sense and avoid” capability.

As such, some of the special operations outlined in 4.1.2 might even imply to enter an

uncontrolled air space in order to achieve a full coverage of the flight task for some

instances.



Date: 10.12.01page 55

The necessary confirmation by a safety case and test phase is a demanding task. For this

reason and the still pending technical maturity (not feasibility), the realisation lies in the

future.

5.2 Procedures

The definition of adequate procedures for all applications as outlined in Chapter 5.1.1, 5.1.2

and 5.1.3 has also to be taken into account the procedures and requirements for transitions

between different air spaces and UAV operations. These procedures have to conform with

intentions and tasks of other related traffic.

In order to verify and optimise the procedures proposed simulation scenarios with other

related civil / military traffic will be applied. These Investigations can be assisted by the Air

Defence Testbed Simulation Tool which is in use within IABG.

Summarising the results and considerations of preceding chapters an initial assessment of

required ATM procedues is described in the following Table 5-1. The entries in the left

column represent the phases of flight or operation as outlined in chapter 3.6.3. The following

column adresses impacts of UAV operations on the current ATM environment and as such

on other related traffic, as it is discussed in details in Chapter 4. The right column describes a

proposed change to the technology and / or a new requirement to ATM to be further

established in the form of an according procedure.



Date: 10.12.01page 56

Phase of Flight Impact of UAV Ops on ATM ATM Requirement / Procedure

Flight Planning Flight Plan does currently not address UAV

specific items.

Flight plan should address:

- Type mass and performence of the UAV,

- Level of autonomy as specified by Appendix J;

- Plans for emergency cases (e.g. recover plan for loss of ATC or Control data link);

- Intention for special operation of flight (Entry/Re-entry point of SUA).

Ground Movement Technologies for safe an orderly ground

movement of UAVs are currently not available

(collision avoidance / obstacle identification and

ground based high resolution navigation) and

not supported by current airport infrastructure.

ATM requirement to establish sufficient ground based devices (e. g. Radar, differential GPS).

Procedures which enable UAVs to perform autonomous ground movements under control of ATC

will assumingly rely on a full synthetic cockpit vision system for the UCS station, whereas the

cockpit vision data may be gained from Radar or Infrared camera devices.

Procedures for failures during ground operations (e. g. Loss of Data Link, Disorientation) have to

be developed.

Take off Take off performance for many UAVs is less

than for passenger and transport aircraft.

If low take off performance of the UAV conflicts to current noise abatement or safety

requirements, UAV operations are not possible unless alternative less excess-power required

procedures for UAVs in the given environment could be defined.

Generally special UAV-related procedures are required for :

- Engine failure / Power degradation during take off need to be identified immediately by

onboard failure identification procedures

- Loss of ATC/CTR data link (“silent” procedure according to flight plan agreement for this event,

safe and immediate identification of loss of ATC data link),

- Loss of UAV control data link / controllability (minimum level of autonomy must ensure a safe

and stabilised climb according to flight plan agreement for this event, safe and immediate

identification of loss of control data link via some contineous performed onboard self-tests)

– Loss of Navigation / Avionics (Loss of air-data functionallity implies severe impact on safety of

flight since take off is performed in low altitudes in lower speed regime; safe and immediate

identification of failure via some contineous performed onboard self-tests is necessary).



Date: 10.12.01page 57

Departure and Climb Climb performance for many UAVs is less than

for passenger and transport aircraft.

Special departure procedures for UAVs with low excess power / small climb rate are required for

operations at large civil airports. Other requirements as for “take off”-phase.

Cruise UAV border crossing is not addressed by

current regulations;

autonomous “see and avoid” principle partly

supported by current technologies but not

addressed by airworthiness requirements;

UAV manoeuverability and speed regime

limitations may conflict with other related traffic;

Nations have to provide an commonly agreed environment for UAV border crossing operations

with respect to airworthiness standardisation, procedures for handling of failure cases, data link

technologies, standards for qualification of UAV control authorities and personnel, clearing of on

board customs.

Procedures/technologies for flying or passing through uncontrolled airspace need to be developed

for certain UAV applications. The problem has to be resolved twofold by development of adequate

“sense and avoid technologies” which are certifiably and on the other hand by the devolpment of

correponding procedures. Some supporting aid for a general solution may be gained if some

general transponder – obligations were to be introduced.

Possible solutions for the short term may be a temporary reserved airspace for UAV flight in the

uncontrolled airspace;.

Special separation procedures need to be implemented or the UAV have to meet minimum design

requirements.

Generally special UAV-related procedures are required for :

- Engine Power loss degradation during cruise requires recognition and identification procedure at

UCS operator, descent and deconfliction procedures have to be developed,

– Loss of ATC/CTR data link (“silent” procedure according to flight plan agreement for this event,

safe and immediate identification of loss of ATC data link, depending on the flight plan

agreement and the level of autonomy an automatic return and landing on a special landing

site/airfield may be possible),

- Loss of UAV control data link / controllability (minimum level of autonomy must ensure a safe

and stabilised flight. according to flight plan, safe and immediate identification of loss of control

data link via some contineous performed onboard self-tests),

- Loss of Navigation / Avionics (Loss of Air-data functionallity implies severe impact on safety of

flight, since high altitude flying highly relies on the Air Data System and as such on a Flight



Date: 10.12.01page 58

Control System (FCS). Loss of Navigation system may imply severe conflicts to other related

traffic and requires some sort of immediate procedures to be taken by other related traffic which

potentially could be interferred by the hampered UAV. As such the loss of Navigation / Avionics

has to be immediately indicated to the UCS operatior. Adequate separation has to be provided by

ATC services.

Special Operation /

mil. Mission

Leaving / Re-entering the air-route system and /

or the civil managed airspace induces

implications / restraints for other related traffic.

ATC has to provide sufficient separation distance in case if a UAV re-enters the air-route system.

Flight plan has to address the intented operation which will be assumed to be conducted in a SUA

in many cases.

Other Failures are treated as for the cruise phase respectivley.

Descent and arrival Currently descent and arrival for civil UAV in

presence with manned aircrafts has not been

addressed by current regulations;

UAV manoeuverability and speed regime

limitations may conflict with other related traffic;

Safe separation procedures have to be developed which also take into account further

deconfliction measures in case of failures; procedures for immediate identification of failures have

to be developed and established by the on-board self test devices of the UAV.

Other failure cases apply as for the take off phase.

Approach and

Landing

Regulations for UAVs have not been

established;

Procedures have to be developed for the approach in IMC. Decisive features for procedures for

go around manoeuvers (abandoned/balked landing if no visual contact to the runway occurs at

the decision height) need to be identified.

Other failure cases apply as for the take off phase.

Table 5-1 - Requirement on ATM for Integration of UAVs



Date: 10.12.01page 59

5.3 Integration of UAV into different Airspace Categories

In this chapter, the decisive features for the integration effort of UAV into the different

airspace categories are defined and referred to the different airspace categories. Additionally

a brief estimation of the effort required will be given.

5.3.1 Definition of Decisive Features and UAV Integration Effort

Concerning the ICAO Airspace Categories, among others, the following features are decisive

for ATM:

• flight (IFR/VFR)

• separation provided

• service provided

• radio communication requirement

• subject to ATC clearance

The ICAO regulations do not take into account any UAV-operation until now.

The following Table 5-2 gives a brief allocation between these decisive features and the

present ICAO-classification.

The previous consideration concerning use of airspace in VMC and IMC give the factors,

potentially affecting conventional separation safety. From these items, a preliminary

classification for the complexity of UAV integration effort into the respective airspace, is

developed.

1 minor integration effort:

equipment and procedures of manned aircraft can be adopted with minor changes and

adaptations

2 moderate integration effort:

equipment must be sophisticated and requires eventually further development.

Procedures must be significantly adapted.

3 considerable and complex integration effort expected:

Development of additional equipment, adaptation of present procedures and eventual

generation of new procedure are necessary. Also though continuous guidance by a



Date: 10.12.01page 60

UCS/operator is foreseen, a high degree of automatic (Artificial Intelligence-) functions is

mandatory. The fact, that traffic, unknown to ATC, may occur, evokes the need for highly

sophisticated sense and avoid, to give at least the operator or the onboard decision

making algorithms the necessary situational awareness.

The following features are valid for the 3 classes of UAV integration effort:

• Need for “sense and avoid” is increasing from 1 to 3

• Provided ATC surveillance is diminishing from 1 to 3

• Unknown traffic is not present in 1 but expected to a certain extent in 2 and to a highextent in 3

This preliminary integration effort does not yet take into account the requirements for and

definition of equipment as well as requirements for a certain degree of autonomy. Refer to

Appendix J – Autonomous Flight.



Date: 10.12.01page 61

5.3.2 UAV Integration into Present Airspace Classes

Class Controlled

airspace

Type of flight Separation

provided

Service provided Speed limitation *) Radio / Data Link

communication

requirement

Subject to an

ATC

clearance

Expected

effort for

UAV

integration

A yes IFR All aircraft All traffic control service Not applicable Continuous two-way Yes minor

IFR All aircraft Air traffic control service Not applicable Continuous two-way YesB yes

VFR All aircraft Air traffic control service Not applicable Continuous two-way Yesmoderate

IFR IFR from IFR

IFR from VFR

Air traffic control service Not applicable Continuous two-way yes

C yes

VFR VFR from IFR 1) Air traffic control service

for separation from IFR;

2) VFR/VFR traffic inform.

(and traffic avoidance

advice on request)

250 kt IAS below

3.050 m (10.000 ft) AMSL

Continuous two-way yes

moderate

IFR IFR from IFR Air traffic control service,

traffic information about VFR

flights (and traffic avoidance

advice on request)

250 kts IAS below

3.050 m (10.000 ft) AMSL


D yes

VFR Nil IFR/VFR and VFR/VFR traffic

information (and traffic

avoidance advice on request)

250 kt IAS below

3.050 m (10.000 ft) AMSL


moderate



Date: 10.12.01page 62

IFR IFR from IFR Air traffic control service and,

as far as practical, traffic

information about VFR flights

250 kts IAS below

3.050 m (10.000 ft) AMSL


E yes

VFR Nil Traffic information as far as

practical

250 kts IAS below

3.050 m (10.000 ft) AMSL

No No

moderate to

complex

depending on

meteorologica

l visibility (3 in

VMC)

IFR IFR from IFR as

far as practical

Air traffic advisory service,

flight information service

250 kts IAS below

3.050 m (10.000 ft) AMSL

Continuous two-way No

F noVFR Nil Flight information service 250 kts IAS below

3.050 m (10.000 ft) AMSL

No Nocomplex

IFR Nil Flight information service 250 kts IAS below

3.050 m (10.000 ft) AMSL

No No

G noVFR Nil Flight information service 250 kts IAS below

3.050 m (10.000 ft) AMSL

No Nocomplex

*) When the height of the transition altitude is lower than 3.050 m (10.000 ft) AMSL, FL 100 should be used in lieu of 10.000 ft.

The expected effort for UAV integration may be higher in general and depend on traffic situation if C or D is a CTR.

Table 5-2 - Estimated Effort for UAV Integration into Present Airspace Classification



Date: 10.12.01page 63

5.3.3 UAV Integration into Future Airspace Categories

With respect to the “Traffic Environment Model” (adoption throughout Europe in the future)

the same features are decisive (Appendix D). But this airspace organisation is based on the

knowledge of traffic and omits the differentiation between controlled airspace and outside

controlled airspace.

The type of flight, the separation and service provided, speed limitations, communications

and clearance requirements will be based on current procedures, but are to be defined.



Date: 10.12.01page 64

Category

EURO

Control

ICAO

Class

type of flightseparation

provided

service

provided

radio / Data Link

communication

requirement

subject to an ATC

clearance

expected effort for

UAV integration

U

E

F

G

not all traffic is known to ATS;

other items (separation and service

provided) are under preparation by

respective authorities.

continuous two way

communication and

transponder not always

required

traffic not always

subject to ATC

clearancecomplex

KE

F

all traffic is known to ATS, either with

position only or with flight intentions as well;

other items (separation and service

provided) are under preparation by


continuous two way

communication and may

be required transponder

always

not all traffic subject to

ATC clearance

minor to moderate

N

A

B

C, D

all traffic is known to ATS with position and

flight intention; other items (separation and

service provided) are under preparation by


continuous two way

communication and

transponder airways

required

all traffic subject to

ATC clearanceminor

Current ICAO specifications for the establishment of controlled airspace will be applied to establish “N” or “K” airspace, the rest of airspace will

then be called “U” Airspace. As in future “U” airspace not all VFR traffic will be known to ATS, ATC can only be provided to/between IFR flights in

“Unknown Traffic Environment”. Current ICAO VMC conditions above 3000’AMSL-1000’AGL will continue to be apply to ensure visual separation

from VFR. But, when IFR flights are expected below such a flight level or when visual separation is considered as safety critical for IFR flights,

“N” or “K” airspace will be established.

Table 5-3 - Estimated Effort for UAV Integration into Future Airspace Classification



Date: 10.12.01page 65

6 Follow-up Study Proposal

6.1 Contents and Objectives

The intention of the current preliminary study is to contribute to the most adequate and safe

solution for the Integration of today’s and future UAVs into ATM concepts in order enable

Eurocontrol to expand and prepare its service to future utilisation of airspace.

Consequently, implications on other related traffic resulting from UAV operations have been

initially identified.

A separatly reported workplan has been performed which covers the initial two years of the

follow-up study. The first step aims at the preparation of procedures and requirements as a

further development of the outcome of this preliminary study.

Parallel to this work a simulation environment will be prepared for further analysis and

verification of the proposed procedures. The main task for this activity will be the

implementation of failure modes of the data / sensor link at an adquate level of description.

The basis for these simulation environment is the Extended Air Defence Testbed Tool and

the MILSIM Environment, both of which are in use for different projects since many years at

IABG.

The Simulation will be used as a tool to improve the understanding of problem areas and in

the second step for optimisation of the solution proposed. Consequently, the workplan

foresees two simulation trials within the initial two years. After that time an initial set of

requirements for the integration of UAVs into an ATM environment and procedures for the

operation of civil UAVs in a commonly used airspace will be suggested.

For the follow-up study a co-ordination with other activities (e.g. EU-funded studies) is

planned with the consent of Eurocontrol.

Further information concerning the detailed workplan, the feasibility and costs of the follow-

up study will be provided separatly.



Date: 10.12.01page 66

6.2 Simulation Tools

6.2.1 MILSIM Simulation Environment

The MILSIM (Man-In-the-Loop Simulator) environment is applied for several applications and

investigations since many years. As such it has been continously further developed.

IOS-Control

Figure 6-1 – Structure of the MILSIM Environment

Figure 6 – 1 describes briefly the structure which consists of two enhanced vision simulation

environments. This tool can be used in combination either to generate the cockpit view of

manned aircrafts, or with closer reference to the UAV aspect, for the generation of a virtual

UAV-cockpit vision which could be used in the UCS. For such application the UCS operator

will be supported with an environment which enables the opeator for virtual airspace

observation from an on-board position.

The MILSIM simulator features a highly modular design and structure. This is necessary in

order to adapt the system to the wide range of different applications. With respect to a

possible cockpit display arrangement for a conventional military aircraft Figure 6-2 provides a

brief impression. All displays and indicators as shown on the figure can be easily modified or

changed in order to display other information.

Cockpit B Cockpit A

Stations



Date: 10.12.01page 67

Figure 6-2 - Head Down Display – Navigation Configuration



Date: 10.12.01page 68

6.2.2 Extended Air Defence Testbed

The Extended Air Defence Testbed Simulator provides a scenario simulation which could be

typically used for the flight planning and operation control of a UAV. The tool has an

establised link to the MILSIM environment also. As such this tool features many different

modes for investigation into different areas of flight conduction. With respect to questions

concerning the data link (e. g. antenna masking effects, etc.) and the situational awareness

concerning the identification of other related traffic, e. g., the tool provides information which

is based on models which have been verified by test data for real systems in most cases.

The tools provides different modes of displaying information. A conventional view to the

overall scenario similar to the infomation displayed to ATC controller is supported by the tool

as well as the view from a position of an airborne observer as shown in Figure 6-3.

Figure 6-3 – Test-Simulation with MALE-UAV in Conjunction with other Traffic



Date: 10.12.01page 69

7 References

[ 1] UAV to get language in FAA Regulations by Leona C. Bull

(http://www.aerotechneurs.Com) downloaded 26.09.2001

[ 2] Highlights of FAA/NASA Joint University Program for Air Transportation

Research (JUP)

(http://act 250.tc.foa.gov/jup/high lights) downloaded 26.09.2001

[ 3] Commercial High Altitude Unpiloted Aerial by Joanne, Irene Gabrywawicz

Remote Sensing. Some Legal Considerations

(http://www.space.edu) downloaded 26.09.2001

[ 4] Commercial UAV Operations in Civil Airspace by Laurence Newcome

www.adroit.com / www.navforum.com

[ 5] First UAV Atlantic crossing

http://www.dsto.defence.gov.an downloaded 24.09.2001

[ 6] Discussion Area 1 – UAV operations and mission planning and tasking

Minutes discussion area 4: Airspace Management and Traffic Deconfliction

http://www.far.org downloaded 25.09.2001

[ 7] “Send in the drones”,

Science and technology article in “The Economist”, November, 10th 2001

[ 8] Strategic Consulting and Market Research for the Aerospace and Defence

industry, Frost & Sullivan Aerospace & Defense,

www.unmannedaircraft.com

[ 9] intentionally left blank

[10] Range Safety Criteria For Unmanned Air Vehicles

Document 323-99

by Range Commanders Council (Range Safety Group)

[11] Unmanned Air Vehicle Operations in UK Airspace – Guidance (Version 1.0)

Directorate of Airspace Policy



Date: 10.12.01page 70

[12] intentionally left blank

[13/14] intentionally left blank

[15] FAA Unmanned Air Vehicle Operations 8/05/96 (Draft)

[16] Summary Report of the Joint EUROCONTROL + NATMC UAV ATM Workshop

Held at EUROCONTROL Brussels 13 – 15 October 1999

[17] CD of the above mentioned workshop

[18] Airspace Policy and Air Traffic Management

UAV System Challenges

Roy André J. Clot

(paper presented at the RTO AVT Course on “Development and Operation of

UAVs for Military and Civil Applications”)

[19] intentionally left blank

[20] A Concept Paper for Separation Safety Modelling

An FAA/EUROCONTROL Co-operative Effort on Air Traffic Modelling for

Separation Standards (20 May 1998)

[21] AC 20-131 B – Airworthiness Approval of TCAS II and Mode S Transponders

(Draft)

[22] EUROCONTROL Airspace strategy for the ECAC STATES

[23] Guidance Material for the Design of Terminal Procedures for DME/DME and

GNSS Area Navigation

[24] JAA Administrative & Guidance Temporary Guidance Leaflet No 10:

Airworthiness and Operational Approval For Precision R-Nav Operations in

Designated European Airspace

[25] UAV integration into ATM; Cl. Le Tallec; ONERA



Date: 10.12.01page 71

8 Appendix A – Tables of UAV

In this Appendix representative UAV for the different UAV classes (0 to 3) are provided. In

particular there are four tables:

• Table A1 – “Class 0”This table shows a representative selection of UAV with a weight of less than 25 kg.

• Table A2 – “Class 1”This table shows a representative selection of UAV with a weight ranging from 25 kg to500 kg.

• Table A3 – “Class 2”This table shows a representative selection of UAV with a weight ranging from 501 kgto 2000 kg.

• Table A4 – “Class 3”This table shows a representative selection of UAV with a weight of more than 2000 kg.

8.1 Explanation of data fields and used abbreviations

• Link TypesThe link-types are divided in

• short wave

• micro wave

• satellite

• analogue

• digital

• ApplicationFor the application type three abbreviations are used:

• TC: Telecommand

• TM: Telemetry

• TV: Television

• Operating Frequency Range

• HF: 1-30 MHz

• VHF / UHF: 30-1000MHz

• L- / S-Band: 1-2 GHz



Date: 10.12.01page 72

• C-Band: 5 GHz

• X-Band: 10 GHz

• Ku-Band: 15 GHz

• Antenna Type

• Narrow Beam

• Omni Directional

• Link ProtectionThere is a wide variety of possible link protections, some are listed below:

• Redundancy

• Frequency Hopping (FHSS)

• Directed narrow Beam Antennas

• Direct Sequence Spread Spectrum (DSSS)

• Channel Coding

• Protocols

• CRC

• Data ProtectionThere is a variety of possible data protections, some are listed below:

• Encryption

• Authentication

The abbreviation “N / A” means that information on this particular point / item is not availableor not regarded as proved to be consistent or correct.



Date: 10.12.01page 73

Table A1: Representative UAV “Class 0” (below 25 kg)

Name Manufacturer NationMax

Weight[kg]

MaxSpeed[kts]

MaxAltitude

[ft]

MaxClimbRate[fpm]

MaxTask

Radius[nmi]

Endurance

[hrs]Data-link Navigation,

Guidance

Lift/PropulsionSystem;Launch &Recovery

Status

Javelin BAI Aerosyst. USA 10 60 3000 6 2 LOS (UHF+L)(C2 & video)

GPS, remotecontrol (VFR)

Fixed wing,piston engine;L: hand or

bungeeR: skid

P

Pointer AeroVironment USA 4.5 40 1000 600 4 0.4(nickel

cadmiumbattery)

LOS(C2 & video)

GPS pre-prog.& remote con

Fixed wing,electric motor;L: handR: deep stall &

belly land

P

Scout 2000 EMT Germany 3 45 1000 3 0.5(nickel

cadmiumbattery)

LOS(C2 & video)

GPS pre-prog.& remote con

Fixed wing,electric motor;L: handR: deep stall &

belly land

D

Conversion of Dimensions: km/h = 1.8532 kts, kg = 0.4536 lbs; ft = 0.3048 m, nmi = 1.8520 km

Data-link: Abbreviations:C2: command & control (up- & down-link) n/a: data not availablevideo: real-time TV, imagery and payload data (down-link) AV Air VehicleFrequency: UHF, L-band C-band. Ku-band, X-band LOS Line of sight

BLOS Beyond line of sightTake-off and Landing IFF transponder for identification (friend or foe)

L: Launch System, e.g. rocket booster, catapult, wheeled DL tracking tracking of the AV (azimuth & elevation) by data link antennaR: Recovery/Landing SystemVTOL Vertical takeoff and landingTOL Takeoff and landingStatus:D: DevelopmentP: ProductionR: Research



Date: 10.12.01page 74

Table A2: Representative UAV “Class 1” (25 - 500 kg)


Weight[kg]

MaxSpeed[kts]

MaxAltitude

[ft]

MaxClimbRate[fpm]

MaxTask

Radius[nmi]

Endur-ance[hrs]

Data-linkNavigation,Guidance


Status

Propeller propulsion system with internal combustion (piston or rotary) or turbo-shaft engines Typical Mission Radius < 100 nmi

Camcopter SchiebelElectronics

Austria 65 55 990 6 6 LOS (C-band)(C2 & video)

INS + DGPS,pre-prog. &remote control

VTOL, convent.rotor system,(1) piston eng.

P

CL-327(enhancedSentinelCL-227)

Bombardier Canada 350 85 18000 1500 60 6 LOS (C)(C2 & video)

INS + GPS,pre-prog. &remote control

VTOL,coax-rotor, (1)turbo-shafteng.

P

Crecerelle(AVSpectre)

SAGEM France 140 130 11000 40 4 LOS(C2 & video)

GPS (DGPS),pre-prog. &remote con,IFF (Mode IIIC)

Fixed wing,(1) piston eng.;L: catapult,R: parachute

or skid

P

Cypher Sikorsky USA 135 80 5000 20 2.5 LOS (C-band)(C2 & video)


VTOL, ductedcoax-rotor,(1) rotary eng.

D

Exodrone BAI Aerosyst. USA 40 110 10000 2.5 LOS (UHFup-link, L-band down-link)C2 & video

DGPS, pre-prog. & remotecontrol

Fixed wing,(1) piston eng.,L: catapultR: skid, net or

parachute

P

Eye-View IAI Israel 150 110 15000 20 6 LOS(dual C2 &single video)

GPS, pre-prog.& remote con

Fixed wing,(1) piston eng.,wheeled TOL

P

Fox AT2 CAC Systems France 115 > 100 13000 40 5 LOS(C2 & video)

INS + DGPS,pre-prog. &remote control,

Fixed wing,(1) piston eng.,L: catapultR: parachute,

P



Date: 10.12.01page 75


Weight[kg]

MaxSpeed[kts]

MaxAltitude

[ft]

MaxClimbRate[fpm]

MaxTask

Radius[nmi]

Endur-ance[hrs]



Status

belly skidHermes 450 Silver Arrow Israel 450 100 23000 900 > 150

(w comrelay)

24 LOS (C/L)(dual C2 &video)

GPS, pre-prog.& remote con,redundant elect& avionics

Fixed wing,(2) rotary eng.,wheeled TOL

D

KZO(Brevel)

STN ATLAS(Eurodrone)

Germany(FR/GE)

150 100 13000 800 50 3.5 LOS (Ku)(C2 & video)

INS + GPS,pre-prog. &remote control,DL tracking

Fixed wing,(1) piston eng.,L: boosterR: parachute

D

LUNAX-2000

EMT Germany 30 70 13000 600 30 3 LOS (C)(C2 & video)

DGPS, pre-prog. & remotecontrol

Fixed wing,(1) piston eng.,L: catapultR:parachute

D

Mart Mk II Altec Ind. France 110 120 10000 1000 40 4 LOS(C2 & video)

remote controlbased on videoand GPS


belly skid

P

Mirach 26 Meteor CAE Italy 200 120 11000 590 50 6 LOS(C2 & video)

GPS/autopilot,pre-prog. &remote con

Fixed wing,(1) piston eng.,L: boosterR: parachute

P

Outrider AlliantTechsystems

USA 220 125 15000 1600 100 5 LOS (C)(C2 & video)

INS + GPS,pre-prog. &remote controlIFF (Mode IIIC)

Fixed wing,(1) piston eng.,wheeled TOL(autoland)

Can-celled1998

Pathfinder AeroVironment USA 250 30 70000 16 Fixed wing,solar powered,wheeled TOL

R

Phoenix GEC-MarconiAvionics

UK 180 90 > 6000 40 5 LOS (J)(C2 & video)

(n/a)pre-prog. &remote control

Fixed wing,(1) piston eng.,L: catapultR: parachute

P



Date: 10.12.01page 76


Weight[kg]

MaxSpeed[kts]

MaxAltitude

[ft]

MaxClimbRate[fpm]

MaxTask

Radius[nmi]

Endur-ance[hrs]



Status

Pioneer Pioneer UAV(AAI/IAI)

USA 200 100 12000 800 100 5 LOS (C+UHF)(C2 & video)

GPS pre-prog.& remote con,IFF (Mode IIIC)

Fixed wing,(1) piston eng.,L: wheeled or

catapultR: wheeled w

tailhook ornet

P

Ranger Orlikon-Contraves

Switzer-land

270 120 15000 750 90 5 LOS (UHF +Microwave)(C2 & video)


Fixed wing,piston eng.,L: catapultR: skid auto-

land

P

Raven FlightRefuelling Ltd.

UK 85 110 14000 50 4 LOS(C2 & video)



belly skid

D

RPG Midget- MkII

- MkIII

TechMent(VTOL) Sweden 50

90

70

80

30

40

3

4

LOS (C+UHF)(C2 & video)


Gyroplane(VTOL+fixed wing)conv. rotor,(1) piston eng.,near vertical orwheeled TOL

P

SearcherMk II

IAI Israel 420 110 20000 110 15 LOS(dual C2 &single video)

GPS,pre-prog. &remote control


P

Shadow200

AAI USA 150 120 15000 70 5 LOS (C+UHF)dual C2 &single video,IFF Mode IIIC

GPS, pre-prog.& remote con,DL tracking

Fixed wing,(1) rotary eng.,L: rail or wheelR: wheel with

tailhook, or

P



Date: 10.12.01page 77


Weight[kg]

MaxSpeed[kts]

MaxAltitude

[ft]

MaxClimbRate[fpm]

MaxTask

Radius[nmi]

Endur-ance[hrs]



Status

parachuteShadow600

AAI USA 270 110 16000 110 14 LOS (C+UHF)dual C2 &single video,

GPS, pre-prog.& remote con,DL tracking


P

Skyeye BAE Systems(USA)

USA 350 110 15000 750 80 10 LOS(C2 & video)

INS+GPS,remote control,video tracking

Fixed wing,(1) rotary eng.,L: catapultR: parachute,

belly skid

P

Spectre II NorthropGrumman &Meggitt TargetSystems

USA/UK 160 140 13000 80 6 LOS(C2 & video)

GPS, pre-prog.& remote con,RF tracking

Fixed wing,(1) piston eng.,L: catapultR: belly skid or

parachute

P

Sperwer SAGEM France 320 130 17000 80 4 LOS (Ku-band) videodown-link


Fixed wing,(1) piston eng.,L: catapultR: parachute

P

Propulsion: TurbojetTypical Mission Radius < 200 nmi

CL 289 EADS Dornier,Bombardier,SAT

GermanyCanadaFrance

240 400 10000 5000 100 0.5 LOS (onlydown-link forIR-video)

Gyro’s & GPS,radar doppleraltimeter &navigation syst

Cross wing,(1) turbojet engL: boosterR: parachute

P

Mirach 150 Meteor CAE Italy 340 400 29000 5000 200 1.2 LOS(C2 & video)

GPS/autopilot,pre-prog. &remote control

Fixed wing,(1) turbojet engL: booster or

air launchedR: parachute

P

Sperwer HV(highvelocity)

SAGEM France 400 400 30000 250(w comrelay)

1.5 LOS (Ku)(C2 & video)


Fixed wing,(1) turbojet eng

Demo



Date: 10.12.01page 78

Table A3: Representative UAV “Class 2” (501 - 2000 kg)


Weight[kg]

MaxSpeed[kts]

MaxAltitude

[ft]

MaxClimbRate[fpm]

MaxTask

Radius[nmi]

Endur-ance[hrs]



Status

Altus GeneralAtomics

USA 1000 100 45000 24 LOS (C-band) INS + GPS,pre-prog. &remote control

Fixed wing,(1) piston eng. +1-stage turbo-charger,wheeled TOL

P

A160Hummingbird

FrontierSystems

USA 1800 30000 24 VTOL, hingelessrigid rotor,(1) piston eng.

Demo

Dragon Fly(CanardRotor/Wing)

Boeing USA 810 400 10000 150 4 INS + GPS,pre-prog. &remote control

VTOL, jetdrivenrotor/wing,(1) low-bypassturbofan engine

Demo

Eagle 1 EADS/IAI France,Israel

1200 110 20000 500 24 LOS &SATCOM


Demo

Eagle-Eye Bell Helicopter USA 1000 200 20000 110 8 LOS (C+UHF)dual up (C2)& single down

Pre-prog. &remote control,

VTOL+fixedwing, tiltrotor,(1) turboshaftengine

Demo

Fire ScoutModel 379

NorthropGrumman,Ryan

USA 1150 135 20000 110(250withcom

relay)

6 LOS (TCDL)(Ku+UHF/VHF) (C2 &video)

INS + GPS,pre-prog. &remote control,IFF transpond.,RF tracking

VTOL, conv.rotor system, (1)turboshaft eng.(automatic VTOLon land & ship)

D(Navy)



Date: 10.12.01page 79


Weight[kg]

MaxSpeed[kts]

MaxAltitude

[ft]

MaxClimbRate[fpm]

MaxTask

Radius[nmi]

Endur-ance[hrs]



Status

I-Gnat(improvedGnat 750)

GeneralAtomics

USA 700 110 25000 1000 200(w comrelay)

40 LOS (C)(4.4-5 / 5.2-5.8 GHz)(dual C2 &dual video)

GPS (INSoptional), pre-prog. & remotecontrol,IFF (Mode IIIC)

Fixed wing,(1) pistonengine,wheeled TOL

P

Hermes1500

Silver Arrow Israel 1500 >130 30000 900 > 150(w comrelay)

30 LOS (C/L)(dual C2 &video)

GPS, pre-prog.& remote con,redundant elect& avionics

Fixed wing,(2) piston eng.+ turbocharger,wheeled TOL

D

Heron IAI Israel 1100 120 30000 110(150

w comrelay)

36 LOS(dual C2 &dual video)

GPS (optionINS), pre-prog.& remote con,redundant FCS

Fixed wing,(1) piston eng.+ turbocharger,wheeled TOL

P

Hunter IAI & TRW IsraelUSA

725 110 15000 750 110(150

w comrelay)

12 LOS (C-band,(4.4-5.8 GHz)(dual C2 &dual video)

GPS, pre-prog.& remote cont.,redundant elect& avionics,IFF (Mode IIIC)


P

Perseus B Aurora Flight USA 1100 250 65000 > 3000(withSat-com)

24 LOS &SATCOM(option)

GPS, pre-prog.& remote cont

Fixed wing,(1) piston engwith 3-stageturbocharger,wheeled TOL

Demo



Date: 10.12.01page 80


Weight[kg]

MaxSpeed[kts]

MaxAltitude

[ft]

MaxClimbRate[fpm]

MaxTask

Radius[nmi]

Endur-ance[hrs]



Status

Predator GeneralAtomics

USA 1000 110 25000 800 400(w comrelay orSatcom)

40 LOS (C-band)SATCOM(Ku+UHF)C2 & video

INS + GPS,pre-prog. &remote control,IFF (Mode IIIC)

Fixed wing,(1) piston eng,wheeled TOL

P

Seamos EADS Dornier Germany 1120 90 12000 1000 110 4.5 LOS (C2 &video)Ku 1-10 Mbps,UHF 10 Kbps),BLOS (C2) HF1Kbps


VTOL,coax-rotor, (1)turboshaft eng,(automatic VTOL

on ships)

Defi-nition

CML-UAV(cruisemissile likeUAV)

EADS Germany 1400 600(Mach0.9, SL

20000 550 3 LOS &LEO Satcom(C2 & video),terrain ref.navigation

GPS & INS,pre-prog. &remote control,terrain/imageref. navigation

Sweep wing,(1) turbojet orlow-bypassturbofan eng.,L: air launched

or boosterR: parachute

Study



Date: 10.12.01page 81

Table A4: Representative UAV “Class 3” ( above 2000 kg)

Name Manufacturer, NationMax

Weight[kg]

MaxSpeed[kts]

MaxAltitude

[ft]

MaxClimbRate[fpm]

MaxTask

Radius[nmi]

Endur-ance[hrs]



Status

DarkStar(Tier IIIminus)

LockheedMartin /Boeing

USA 3900 300 50000 2000 500 12 LOS (X-band+ UHF)SATCOM(Ku+UHF)all C2 & video

INS + GPS,pre-prog. &remote control,IFF (Mode IIIC)

Fixed wing,stealth design,(1) turbofanengine,wheeled TOL

Can-celled1999

Eagle 2 EADS France 3600 250 45000 500 20 LOS &SATCOM

Fixed wing,(1) turboprop

Study

GlobalHawk(Tier II plus)

NorthropGrumman(TeledyneRyanAeronautical)

USA 11600 350(Mach

0.6,@ alt)

65000 3400 3000 38 LOS (X-band+ UHF)SATCOM(Ku+UHF)all C2 & video

INS + GPS,pre-prog. &remote control,IFF (Mode I, II,IIIC, IV)

Fixed wing,(1) turbofanengine,wheeled TOL

Demo

Predator B GeneralAtomics

USA 3000 200 50000 >2000 1000 32 LOS (C-band,)SATCOM(Ku+UHF)C2 & video

INS + GPS,pre-prog. &remote control,IFF transpond.

Fixed wing,(1) turbopropengine,wheeled TOL

Demo

X-45SEADUCAV(US Airforce)

Boeing USA 6800 600(Mach

0.9, SL)

45000 n/a 650 3 LOS +SATCOM

INS + GPS,pre-prog. &remote control,autonomousmission phases

Fixed wing,stealth design,(1) low-bypassturbofan eng.with thrustvectoring,wheeled TOL

Demo

X-47UCAV-NPegasus(US Navy)

NorthropGrumman

USA 4500 600(Mach

0.9, SL)

40000 n/a 600 12 Fixed wing,stealth design,(1) low-bypassturbofan eng,wheeled TOL

Demo



Date: 10.12.01page 82

Name Manufacturer, NationMax

Weight[kg]

MaxSpeed[kts]

MaxAltitude

[ft]

MaxClimbRate[fpm]

MaxTask

Radius[nmi]

Endur-ance[hrs]



Status

on carrierGE UCAV(SEAD &strike)

EADS Germany 8200 550(Mach

0.85, SL)

LOS (X-/Ku-band, UHF),SATCOM(Ku+UHF),HF (BLOS)

Fixed wing,stealth design,(1) low-bypassturbofan eng,wheeled TOL

Study



Date: 10.12.01page 83

8.1.1 Illustration of the UAV Categorisation

A visualisation of the spread of main design parameters (e.g. mass, airspeed, etc.) versus

the Maximum Take-Off Weight (MTOW) is outlined for different UAVs. Figure A1 to Figure

A4 provide a visualisation of such data which were selected from Table A1 to A4.

In general these figures do not necessarily describe a functional relationship. As such the

figures describe the scatter in the main design parameter of different UAV. Note that not all

data for each UAV under consideration is available. As indicated by the figures the scatter for

a same mass class results from different design requirements for the UAV which also results

in different propulsion systems.

Figure A-1 - Comparison of max. Airspeed of different UAVs

Figure A-2 - Comparison of max. Altitude of different UAVs

0 200 400 600 800 1000 1200

60

80

100

120

140

160

180

200

Rotary Wing UAVs

Propulsion System: Piston / Rotary Engine Turboshaft

max

. Airs

peed

[kts

]

max. Take-Off weight [kg]0 2000 4000 6000 8000 10000 12000

0

50

100

150

200

250

300

350

400

450

500

550

600

Fixed Wing UAVs

Propulsion System: Piston / Rotary Engine Turboprop Turbojet / -fan Electric / Solar

max

. Airs

peed

[kts

]

max. Take-Off Weight [kg]

0 2000 4000 6000 8000 10000 120000

10000

20000

30000

40000

50000

60000

70000

80000

Fixed Wing UAVs


max

. Alti

tude

[ft]

max. Take-Off Weight [kg]0 250 500 750 1000 1250 1500 1750 2000

0

5000

10000

15000

20000

25000

30000

Rotary Wing UAVs


max

. Alti

tude

[ft]




Date: 10.12.01page 84

Figure A-3 - Comparison of max. Mission Radius of different UAVs

Figure A-4 - Comparison of max. Climb Rate of different UAVs in Sea Level

0 200 400 600 800 1000 12000

50

100

150

200

250

Rotary Wing UAVs


max

. Mis

sion

Rad

ius

[nm

i]

max. Take-Off Weight [kg]0 2000 4000 6000 8000 10000 12000

0

500

1000

1500

2000

2500

3000

Fixed Wing UAVs


max

. Mis

sion

Rad

ius

[nm

i]


0 2000 4000 6000 8000 10000 120000

1000

2000

3000

4000

5000

Fixed Wing UAVs

Propulsion System: Piston / Rotary Engine Turboprop Turbojet / -fan Electric / Solarm

ax. C

limb

Rat

e [ft

/min

]


0 200 400 600 800 1000 12000

250

500

750

1000

1250

1500

Rotary Wing UAVs


max

. Clim

b R

ate

[ft/m

in]




Date: 10.12.01page 85

9 Appendix B – Representative Examples for UAV

In this appendix some selected representatives of each UAV class is introduced in more

details.

9.1 Class 0 - SCOUT 2000

Manufacturer: EMT Ingenieurgesellschaft mbH, Germany

System: Close-range Mini UAV for reconnaissance, surveillance and target

acquisition. Customer: German Army.

Propulsion: One electric motor, 300 W, two-blade propeller powered by nickel

cadmium or lithium batteries

Payload: Colour TV video camera with zoom, forward and down looking,

option: night sight sensor

Navigation: GPS based pre-programmed way-point navigation or manual

control



Date: 10.12.01page 86

Datalink: LOS real time bi-directional datalink for command, control and

video

Launch & Recovery: Hand start and deep stall to belly landing

Control Station: Portable, laptop-like control station for command, control and video

display

Technical Data:

Takeoff Weight: 3 kg

Wingspan: 5 ft

Length: 5 ft

Payload: 1 kg

Fuel: Batteries

Flight Altitude: 100 ft – 1000 ft

Speed: 25 kts – 50 kts

Mission Radius: 3 nmi

Endurance: 0.5 hrs (nickel cadmium) or 2 hrs (lithium batteries))



Date: 10.12.01page 87

9.2 Class 1 - KZO (Brevel)

Manufacturer: STN ATLAS Elektronik GmbH, Germany

System: Short-range Tactical UAV for surveillance, target acquisition &

designation and battle damage assessment. Customer: German

Army.

Propulsion: One two-stroke, two-cylinder 30 hp piston engine, F&S/Schrick,

two-blade pusher propeller

Payload: Zeiss Ophelios gimbal mounted, stabilized IR-sensor with zoom,

forward, down and side looking. Options: communication jammer

(UAV Mücke) or signal detection/analysis (UAV Fledermaus)

Navigation: INS/GPS based pre-programmed way-point navigation and remote

control, navigation backup: tracking by the high precision narrow

beam data-link antenna on ground (rho/theta)

Datalink: LOS real time bi-directional Ku-band datalink, high jamming

resistance, (uplink for vehicle & sensor control, downlink for IR-

video and telemetry data)

Launch & Recovery: Rocket booster start and parachute / airbag landing

Control Station: Ground Control Station (GCS) with three work stations:

– one for mission planning, vehicle control and guidance,

– one for real time image exploitation and target acquisition,



Date: 10.12.01page 88

– one for target verification and tactical communication of the

commander.

The GCS is linked to the separate data-link ground terminal by a

robust fibre optical cable and contains a full mission sensor and

flight data recorder

Technical Data:


Wingspan: 11 ft

Length: 7 ft

Payload: 30 kg

Fuel: 25 kg MOGAS

Flight Altitude: 1000 ft – 13000 ft


Max Climb Rate: 800 fpm


Endurance: 3.5 hrs



Date: 10.12.01page 89

9.3 Class 1 - OUTRIDER

Manufacturer: Alliant Techsystems Inc., USA

System: Short-range Tactical UAV for reconnaissance, surveillance and

target acquisition. Designed for US Army, Marine Corps and Navy

Propulsion: One 50 hp rotary engine UEL AR801R, two-blade pusher propeller

Payload: Gimbal mounted, stabilised EO/IR-sensor with zoom, forward,

down and side looking. Options: SAR (growth)


control, GPS auto-land system

Datalink: LOS real time bi-directional C-band analogue data-link (digital

growth), bandwidth 20 MHz with embedded 19.2 kbps C2 &

telemetry channel (up-link for vehicle & sensor control, down-link

for IR-video and telemetry data)

Launch & Recovery: Wheeled takeoff and landing on unprepared runways and large

ship decks

Control Station: Ground Control Station with two work stations:


– one for real time image exploitation, target acquisition and

tactical communication.



Date: 10.12.01page 90

Technical Data:


Wingspan: 13 ft

Length: 11 ft

Payload: 27 kg

Fuel: 35 kg AVGAS/MOGAS

Flight Altitude: up to 15000 ft




Endurance: 5 hrs



Date: 10.12.01page 91

9.4 Class 2 - PREDATOR

Manufacturer: General Atomics Aeronautical Systems Inc., USA

System: Medium-range Endurance UAV (beyond line-of-sight with SAT-

COM) for reconnaissance, surveillance, target acquisition

/designation, electronic warfare, communication relay and signal

intelligence (SIGINT). Customer: US Department of Defence

Propulsion: One four-stroke, four-cylinder fuel injected 100 hp Rotax 914

piston engine with two-blade variable-pitch pusher propeller

Payload: Gimbal mounted, stabilised EO/IR-sensor with zoom, forward,

down and side looking, laser range-finder / designator and SAR.

Options: SIGINT and jam equipment, communication relay


control, IFF transponder Mode IIIC, VHF/UHF radio for ATC voice

relay

Datalink: Real time bi-directional C-band LOS data-link (20 MHz bandwidth),

UHF and Ku-band SATCOM (64 kbps up-link for vehicle & sensor

control, 1.5 Mbps down-link for EO/IR imagery, SAR and telemetry

data)

Launch & Recovery: Conventional wheeled takeoff and landing

Control Station: Ground Control Station with two work stations:


– one for real time image exploitation, target acquisition and



Date: 10.12.01page 92

tactical communication.

Technical Data:


Wingspan: 49 ft

Length: 27 ft

Payload: 200 kg

Fuel: 300 kg AVGAS/MOGAS

Flight Altitude: up to 25000 ft




Endurance: 40 hrs



Date: 10.12.01page 93

9.5 Class 3 - Global Hawk

Manufacturer: Northrop Grumman, Teledyne Ryan Aeronautical, USA

System: Long-range, high altitude, long endurance UAV (beyond line-of-

sight with SATCOM) for reconnaissance, surveillance signal

intelligence (SIGINT) and communication relay. Customer: US Air

Force

Propulsion: One Allison Rolls-Royce AE 3007H turbofan engine (bypass ratio

5) rated at 7050 lbF sea level static thrust

Payload: SAR/MTI and high resolution electro-optical camera & infrared (3-5

µm) sensor. Both sensors are gyro-stabilised (3 mrad) and gimbal

mounted to allow down and side looking. The SAR sensor

provides spot and wide-area search mode operation and the

EO/IR sensors are looking through a common long range zoom

optical system (6 ft focal length, 11 inch aperture diameter). Future

payloads include SIGINT and communication relay equipment



Date: 10.12.01page 94


control, IFF transponder Mode I, II, IIIC and IV,

Data-link: Multiple real time bi-directional data-links:

Line-of-sight: UHF (9.6/9.6 kbps) and X-band (200kbps/137Mbps)

LOS data-links

Beyond line-of-sight: UHF (9.6/9.6 kbps) and Ku-band (200kbps/

48Mbps) SATCOM

Command and Control through all data-links (UHF 9.6 kbps,

X-band LOS and Ku-band SATCOM 200 kbps),

EO/IR/SAR imagery through X-band LOS (137 Mbps) or Ku-band

(48 Mbps) STACOM down-links

Self Defence: Threat warning receiver , onboard jammer, towed decoy

(repeater/deception transmitter)

Launch & Recovery: Conventional wheeled takeoff and landing

Control Station: Ground Control Stations:– Launch and Recovery Element (LRE) with two operators for vehicle control during takeoff, approach and landing and communication with ATC (shelter size 8 x 8 x10 ft),– Mission Control Element (MCE) with 5 operator places for mission planning, vehicle control and guidance, sensor control, EO/IR/SAR image exploitation and communication to air commander and ATC (shelter size 8 x 8 x 24 ft).

Technical Data:


Wingspan: 116 ft

Length: 45 ft

Payload: 900 kg

Fuel: 6650 kg Heavy Fuel (JP-8)

Flight Altitude: 50000 ft - 65000 ft

Speed: 340 kts at high altitude



Endurance: 38 hrs (20 hrs at 3000 nmi)



Date: 10.12.01page 95

10 Appendix C - Examples of Datalinks

10.1 UAV “Mücke”

The Mücke UAV is a small military system with a high degree of flight autonomy, used for

jamming missions in the VHF frequency range and higher. As this spectrum cannot be used

for the data link, UAV control and monitoring data are transferred via HF, which provides a

data rate of 1 Kbps.

Tasks of the control link are:

• Mission plan update

• Position request & reporting

• Technical status

• Jammer control

Mücke: Link Characteristics

Link Type Analogue Microwave Data Link, 2 parallel channels

Application TC / up-link (Mission Plan Update, Jammer Control, UAV-StatusRequest, Position Request);

TM / down-link (UAV-Status, Position Reporting)

Communication Mode semi duplex

Operating FrequencyRange

HF

Bandwidth/Data Rate 1 Kbps

Link Range < 220 NM

Antenna Type Horizontal Dipole Antenna

Link Protection FHSS

Data Protection N / A

(Transmitter Power) 30 Watts

ATC N / A



Date: 10.12.01page 96

10.2 UAV KZO / BREVEL

KZO/BREVEL: Link Characteristics

Link Digital Microwave Data Link; 3 channels

Application Channel 1: TC ( Up-link);

Channel 2: TM (Down-link);

Channel 3: TV (Down-link)

Communication Mode full duplex on all channels


KU-Band

Bandwidth / Data Rate TC: (N / A) / 10 Kbps

TM: (N / A) / 10 Kbps

TV: (N / A) / 10 Mbps

Link Range > 80 NM / LOS

Antenna Type 2-axis directed Narrow Beam

Link Protection Directed narrow Beam Antenna; DSSS; FHSS; Interleaving

Data Protection Error Recognition / Correction by FEC-Codes

(Transmitter Power) self adaptive

ATC N / A



Date: 10.12.01page 97

10.3 UAV PIONEER

The Pioneer has two links:

• a main up- / down-link for Command & Control, B/W-video and Telemetry

• a secondary up-link for Command & Control data

Pioneer: Link 1 Link 2

Link Digital (N / A) Microwave DataLink

Digital (N / A) Short wave DataLink

Application TC (Up-link)TV [B/W-Video] (Down-link)TM (Up ink)

Secondary Up-link for TC

Communication Mode simplex (N / A) simplex (N / A)


C-Band;4.43 – 4.94 GHz selectable in5 MHz steps

UHF;420 – 450 MHz

Bandwidth / Data Rate 36,36 Mhz/10 MHz (N / AMbps)

600KHz / 7.317Kbps

Link Range • 7 NM (real time video) /LOS

• 18 – 20 NM (C2, TM,non real time video) /LOS

18 – 20 NM

Antenna Type Omni Directional Omni Directional

Link Protection Redundant UHF-Link for TC

Data Protection None (N / A) None (N / A)

(Transmitter Power) (N / A) (N / A)

ATC N / A



Date: 10.12.01page 98

10.4 UAV CL 289

CL 289: Link Characteristics

Link Type Analogue Microwave Data Link

2 parallel channels

Application TC ( Up-link)

TV / down-link (IR-Line Scanner, Video)

Communication Mode simplex (N / A)


L-Band

Bandwidth/Data Rate Ch1: 1,6 MHz (N / A)

Ch1: 1,6 MHz (N / A)

Link Range 28 NM / LOS

Antenna Type Omni Directional

Link Protection, (N / A)

Data Protection (N / A)

(Transmitter Power) self adaptive

ATC N / A



Date: 10.12.01page 99

10.5 UAV Global Hawk

Global Hawk has four independent data communication systems:

• L3 Communications Integrated Communication System as Ku-Band SATCOM

• Command & Control System as UHF SATCOM

• Command & Control System as UHF LOS

• Common Data Link as Microwave LOS

Global Hawk:(Tier II plus)

Link 1 Link 2 Link 3 Link 4

Link Digital SatelliteData Link

Digital SatelliteData Link (DoDUHF Satellite)

DigitalMicrowave DataLink

Digital Shortwave Data Link

Application • TC / to Sat.(UAVstatus)

• TV / to Sat.(ThreatInfo,ImageryData)

• TC/to Sat.(UAVstatus)

• TV/to Sat.(ThreatInfo)

• TC/fromSat.

Common DataLink:

• TC / down-link

• TV / down-link(Imagerydata,ThreatInfo)

TM / down-link

• TC (up-link)

• Voicerelay (up-link)

• UAV-Status(downl-ink)

• Voicerelay(downl-ink)

Communication Mode half duplex(N / A)

half duplex(N / A)

half duplex(N / A)

half duplex(N / A)


Ku-Band UHF X-Band UHF

Bandwidth/Data Rate Return Link: 3 -69 MHz / 1.5 –48 Mbps

Command Link:260 KHz / 200Kbps

25KHz / 9.6Kbps

Return Link: 137MHz / 137 Mbps(48 used)

Command Link:64 MHz / 200Kbps

25 KHz / 9.6Kbps

Link Range dep. on satellitecoverage

dep. on satellitecoverage

LOS LOS (<270 NM)

Antenna Type (N / A) (N / A) (N / A) (N / A)

Link Protection Redundant UHF-Link for TC

Data Protection (N / A)

(Transmitter Power) (N / A) (N / A) (N / A) (N / A)

ATC Transponder Mode 1, 2, 3 C, 4, IFF



Date: 10.12.01page 100

10.6 UAV Predator

Predator:(Tier II)

Link 1 Link 2 Link 3

Link Type Digital Satellite DataLink

Digital Satellite DataLink

Analogue MicrowaveData Link

Application • TC / from Sat.(MissionUpdate,PayloadControl)

• TV / to Sat.(Imagery)

• TM / to Sat.(AV-Status)

(N / A) • TC / up-link

Communication Mode (N / A) (N / A) (N / A)


Ku-Band UHF C-Band

Bandwidth/Data Rate Return Link: 5 MHz /1,544 MbpsCommand Link: 9MHz / n * 64 Kbps

(N / A) 20MHz / 20 MHz

Link Range dep. on satellitecoverage

(N / A) LOS

Antenna Type (N / A) (N / A) (N / A)

Link Protection (N / A)

Data Protection (N / A) (N / A) (N / A)

(Transmitter Power) (N / A) (N / A) (N / A)

ATC Transponder Mode 3 C, IFF



Date: 10.12.01page 101

11 Appendix D – Airspace Categorisation

This appendix contains a brief description of current airspace categorisations and a simplified

long term future categorisation which is planned by EUROCONTROL [22]. Furthermore

some basic description for the utilisation of european airspace were introduced.

11.1 Air Traffic in European Airspace

11.1.1 Basic Terms

In this chapter some basic terms for the further discussion are introduced and explained as

well as the impact on civil UAV operation.

11.1.1.1 Meteorological Conditions

Basically there are two possible meteorological conditions which can occur:

• Instrument Meteorological Conditions (IMC) and

• Visual Meteorological Conditions (VMC).

VMC is prevailing if certain values for visibility and cloud ceiling are given, respectively if a

certain distance to clouds, both lateral and vertical, can be maintained. Whereas IMC is

prevailing if any of the values mentioned above are not given or can not be maintained.

These two meteorological conditions are based on the human eyesight. Thus, they are not

applicable for the control of the UAV itself, but they are decisive with respect to other traffic.

UAVs operate entirely independent on these meteorological conditions.

11.1.1.2 Flight Rules

There are two basic kinds of flight rules:

• Instrument Flight Rules (IFR) and

• Visual Flight Rules (VFR).

Flights can be conducted under one or a mix of these flight rules. Flights under VFR (VFR-

flights) have to be conducted in VMC, that means separation and collision avoidance are

mostly based on “see and avoid”. Flights under IFR (IFR-flights) may be conducted either

under VMC or IMC. In IMC the collision avoidance is primarily based on other means than



Date: 10.12.01page 102

“see and avoid”. In the first approach, UAVs have inherently to be operated as IFR-flights. To

operate UAVs in an environment, where at least some other traffic operates according VFR

rules, mainly based on “see and avoid”, requires special measures, addressed further down.

11.1.2 Airspace Classification

The following part describes the different categories of the present airspace structure.

Thereafter the envisaged future airspace structure is outlined.

11.1.2.1 Present Categories of Airspace

In Europe the airspace is structured basically in the classes A to G. However, the airspace

structures in the European countries differ as well as the applied categories of airspace.

Furthermore, each country may apply slight deviations from ICAO regulations, listed in the

respective AIP (Aeronautical Information Publication.)

For the further discussion, the following simplified structure of airspace is used; it keeps track

of the classes A to G, which can be summarised as follows:

• Controlled airspaceThis airspace is in the primary responsibility of ATM, however, not all traffic in thisairspace is under positive radar control. In controlled airspace IFR-flights and VFR-flights are possible, collision avoidance is in the responsibility of ATC (IFR) and theaircrews (VFR). UAVs have to operate under the responsibility of ATC, VFR flights ofmanned aircraft have to be informed accordingly about UAV flights.

• Uncontrolled AirspaceA relatively small portion of European airspace is uncontrolled airspace. Traffic in thisairspace is normally not in contact with ATM-authorities and therefore mostly unknownto ATC. All flights are supposed to be VFR-flights and collision avoidance is in theresponsibility of the aircrews. UAVs have to avoid uncontrolled airspace. If this is notfeasible, all other traffic has to be informed accordingly, e.g. by NOTAM.

• Special Use AirspaceAll airspace which is used for special purposes, as for example military airspace. Trafficin this airspace is under radar control and must be known to ATC. Most of today’s UAVoperations are restricted to special use airspace.

11.1.2.2 Future Categories of Airspace

The long term Eurocontrol airspace strategy for the ECAC states [22] focuses on only three

categories of airspace in the future. Long term plans will reduce the number of categories to

two. The future categorisation is based on knowledge of traffic and its intent rather than on

the discrimination between controlled and uncontrolled airspace:



Date: 10.12.01page 103

• Airspace NAll traffic and all intentions are known (e. g. an UAV in a pre planned flight for radio/TVtransmission relay)

• Airspace KAll traffic is known, but not all intentions (e. g. an UAV in a flight for environmentalcontrol, area of flight known, but detailed routing according actually detected pollutionIn this case, the UAV has to report its position repeatedly to ATC)

• Airspace UUnknown traffic environment. UAV should avoid this airspace . If this is not feasible,ATC must inform all other traffic, e.g. by NOTAM. Basically, the same conditions applyas for uncontrolled airspace.

11.2 Utilisation of European Airspace

The consequences for the operation of UAV within the respective airspace structure are

discussed in a general manner. Respective overviews are given at the end of the chapter. As

in most parts of this report, the aspects of equipment mass, volume (both affecting especially

small UAV capability considerably) and economic aspects are not addressed.

Any vehicle flying under Instrument Flight Rules is under constant surveillance of ATC.

Vehicles flying VFR are not necessarily under constant surveillance of ATC, but in certain

areas can be subjected to various degrees of surveillance, see below. Further down an

overview is given taking into account the ICAO airspace categories and a Eurocontrol future

traffic environment model.

11.2.1 Controlled Airspace

11.2.1.1 Flights within Controlled Airspace in IMC

All air vehicles, manned aircraft as well as UAVs, flying in IMC, have to fly according IFR and

have to rely on ATC and navigational aids (NAVAIDS) for routing and separation.

Separation and de-confliction is provided by ATC on the basis of:

• Usage of the Air Route Network

• Radar coverage

• time over reporting points

• fixed procedures (e.g. holdings)

• voice communication (data link communication in progress)

• Automated ground based systems, acting in the background, as Short Term ConflictAlert (STCA of the German ATS provider DFS) and others



Date: 10.12.01page 104

These principles are in accordance with the regulations for vertical, longitudinal and lateral

separation.

Additionally, short term collision avoidance can be provided additionally by Airborne Collision

Avoidance Systems (ACAS) respectively Traffic Collision Avoidance Systems (TCAS).

However, aircraft need to have the appropriate equipment.

Presently there are two stages of development for ACAS / TCAS (refer to Appendix E –

Collision Avoidance) introduced:

• ACAS / TCAS ITraffic Advisories (TA) only are generated between fully equipped A/C (intruders withoperating transponders are shown too)

• ACAS / TCAS IITraffic Advisories (TA) and Resolution Advisories (RA) are generated between fullyequipped A/C. (Only climb, descent or maintain altitude, no lateral manoeuvring byturning.)

In the future, ADS-B will contribute in a significant manner to the data exchange between air

traffic participants and ATC in a “ATM 2000+” environment (e.g. Free Routes Airspace or

Free Flight airspace), thus contributing among other advantages to:

• direct routing

• sharing responsibility for separation between ATC and aircrews, when suitable

• conflict probing, long and midterm de-confliction

• short term collision avoidance in the 3-dimensional regime.

Furthermore CPDLC (Controller-Pilot-Data-Link-Communication) will complement the voice

communication.

11.2.1.2 Flights within Controlled Airspace in VMC

Generally within the controlled airspace the collision avoidance is based on separation

measures taken by ATC. Additionally the principle of airspace oberservation for collision

avoidance (“see and avoid”) is applicable for flights in VMC.

Flying according IFR in VMC does not dispense IFR traffic from looking outside (airspace

observation) in order to contribute to collision avoidance when ever visibility allows. It must

be clearly understood that with respect to fast traffic and high closure rates, this “see and

avoid” strategy has a lot of draw backs. As such for IFR traffic this principle of airspace

observation for collision avoidance (“see and avoid”) is of back-up character since all traffic



Date: 10.12.01page 105

movements and positions of other traffic participants within the controlled airspace should be

well known. Basically the collision avoidance is based on separation measures taken by ATC

and additional/optinal on-board collision avoidance systems as mentioned above.

In addition to ATC provided separation measures and procedures VFR traffic has to rely on

the “see and avoid” strategy.

VFR traffic by night in controlled airspace requires at least similar surveillance as IFR-traffic.

In addition, for all VFR flights in controlled airspace, a transponder code is mandatory. Thus,

ATC is not restricted to primary radar alone. Furthermore, TCAS/ACAS devices support the

identification of traffic participants via the transponder signal. The transponder is also

required for all UAV flights in all drafts of UAV equipment. Appropriate small and lightweight

transponders are available on the market.

VFR Air traffic may use traffic information provided by the ATC-Info-Service, if available.

However, usage is not mandatory and info service is not available on a 24 hour basis.

Some degree of separation may be generated by following the non mandatory semi-circular

system.

VFR traffic is prohibited above FL 100, though exceptions are made under certain conditions,

which assure a secure level of control by ATC.

11.2.2 Uncontrolled Airspace

11.2.2.1 Flights within Uncontrolled Airspace in VMC

Uncontrolled airspace is not controlled by ATC and all flights of manned vehicles have to be

conducted under VFR. Therefore the air traffic basically has to detect and solve separation

conflicts by means of “see and avoid”. Additionally some of the aircraft have technical

means, for example transponders, to support in separation provision. However, this

additional equipment is presently not mandatory.

11.2.3 Special Use Airspace

Special Use Airspace (SUA) consists of Airspace of defined dimensions identified by an area

on the surface of the earth wherein activities must be confined because of their nature and/or



Date: 10.12.01page 106

wherein limitations may be imposed upon aircraft operations that are not a part of those

activities.

The different types of special use airspace are:

• Alert Area Airspace

Alert Area Airspace may contain a high volume of pilot training activities or an unusual

type of aerial activity, neither of which is hazardous. Pilots of participating aircraft as

well as pilots transiting the area are equally responsible for collision avoidance. The

same is true for UAVs.

• Controlled Firing Area

Controlled Firing Area is airspace wherein activities are conducted under conditions so

controlled as to eliminate hazards to non participating aircraft and UAV and to ensure

the safety of persons and property on the ground.

• Military Operations Area

Military Operations Area (MOA) is established outside of Class A airspace area to

separate or segregate certain non hazardous military activities from IFR traffic and to

identify for VFR traffic where these activities are conducted.

• Prohibited Area

Prohibited Area, Airspace within which no person may operate an aircraft without the

permission of the using agency.

• Restricted Area

In Restricted Areas the flight of aircraft, while not wholly prohibited, is subject to

restriction. Most restricted areas are designated joint use and IFR/VFR operations in

the area may be authorised by the controlling ATC facility when it is not being utilised

by the using agency. Restricted areas are depicted on en route charts.

• Warning Area

Warning Area- A is airspace of defined dimensions extending from 3 nautical miles

outward from the coast of the United States, that contains activity that may be

hazardous to non participating aircraft. The purpose of such warning area is to warn

non participating pilots of the potential danger. A warning area may be located over

domestic or international waters or both.



Date: 10.12.01page 107

12 Appendix E - Collision Avoidance

This appendix contains considerations concerning Collision Avoidance issues of UAV.

12.1 ACAS / TCAS / ETCAS

Short term collision avoidance is provided, if applicable, additionally by:

• ACAS / TCAS I between fully equipped A/C generates traffic advisories only (Intruderswith operable transponders are shown too)

• ACAS / TCAS II between fully equipped A/C generates traffic advisories and resolutionadvisories. (Only climb, descent or maintain altitude, no lateral manoeuvring.)

• ETCAS (Enhanced TCAS) is a military follow-on development of TCAS, showing allTCAS features and additional functionalities. ETCAS may be especially suitable forUAV due to its enlarged and reshaped warning area.

• Several other active or passive Collision Avoidance devices are available on themarket, mostly intended for smaller and lighter aircraft / helicopters and hence lesssophisticated than ACAS / TCAS

With respect to TCAS/ACAS and UAV the following essential facts (being also true for the

other Collision Avoidance devices) must be clearly understood.

• In TCAS I as well as in TCAS / ACAS II, the display of the horizontal situation i.e. trafficand intruders is mainly thought to help the aircrew in visual perception and tracking oftraffic and intruders, if meteorological and physiological conditions permit.

• Because the azimuth measurement of the direction (bearing) is of reduced accuracy (inTCAS I it is 14 degrees), the TCAS / ACAS display is not suitable for lateral avoidancemanoeuvring. Only altitude information is reliable if Mode C is operable. TCAS II /ACAS II algorithms and resolution advisories are based only on vertical manoeuvres(climb, descent, level keeping and some changes in strength).

• TCAS / ACAS does not incorporate any interface to cockpit automation, but is basedmerely on the avoidance action performed by the cockpit crew.

NOTE:Reference [21], TCAS II Airworthiness Approval, among other parts, reads as follows:“The TCAS II resolution advisory (RA) algorithms are based on the pilot initiating theinitial 0.25 g acceleration manoeuvre within approximately 5 seconds. Pilot response isexpected within approximately 2 – ½ seconds if an additional RA is issued. (Theincrease rate and rate reversal RAs are based on a .35 g acceleration manoeuvre.)Because of these requirements and the rate limits of the auto pilots, all RA responsesmust be hand-flown and not with the auto pilot or auto throttles engaged.”

(Consequences for UAV are discussed above in depth. To cope with the performances of the

UAV certain Resolution Advisories may be inhibited, not to exceed critical limits.)



Date: 10.12.01page 108

TCAS/ACAS display can contribute to safety of an UAV but is far from being the solution for

UAV in general airspace. The requirements of avoidance manoeuvres exceed the rate limits

of present auto pilots of manned aircraft and UAV. Responses to resolution advisories must

be manually flown, auto-throttles disengaged. An aggravating factor is that TCAS, in contrary

to transponder Mode S, is not even mandatory for all IFR traffic

12.2 ADS-B

ADS-B relies on the exact 3-dimensional position and other information (speed, intent etc.

according to the appropriate “surveillance level”). Thus ADS-B exchanges information

suitable for 3-dimensional conflict probing, co-operative long-, mid- and short-term de-

confliction / collision avoidance. ADS-B can be used and is intended to be used as basis for

automation of manoeuvring.

The collision avoidance algorithms must take into account the different performances of UAV

and manned aircraft, to be fully applicable for UAV. Technical considerations concerning

automatic collision avoidance are given further down in Appendix F – Separation Safety.

12.3 Avoidance of Collision with Terrain

Collision avoidance with terrain can be given in a separate redundant manner as in manned

aircraft, by GPWS / TAWS equipment. These items as well do not contain any interface to

automation. Due to the fact, that the usage of civil airspace will not contain extremely low

level flight, terrain collision avoidance is not an “immediate action necessary” item.

Comparison of UAV position with terrain data can be done in the UCS during flight and

during flight planning as well.



Date: 10.12.01page 109

13 Appendix F - Separation Safety

In this appendix the factors, affecting separation safety are listed and discussed with respect

to UAV operation. The factors are taken from “A Concept Paper For Separation Safety

Modelling”, subtitled “An FAA EUROCONTROL Co-operative Effort on Air Traffic Modelling

for Separation Standards” [20]. The structure of the factors is maintained throughout the

discussion in order to enhance cross reference to the original document.

The listed factors are valid for all kinds of separation provided by ATC (e.g. IFR from IFR and

IFR from VFR) and during ATM emergency procedures. Preliminary the factors are used to

look at possible operation of UAVs in commonly used airspace to give some preliminary

results for separation safety for UAV.

The structure of the factors is maintained throughout the discussion in order to enhance

cross reference to the original document [20].

In the left column, the factors of [20] are listed. In the right column, the factors are discussed

with respect to UAV operation. The discussion refers either to a single factor or to the

respective groups of factors.

FACTORS affecting separation safety DISCUSSION with respect to UAV

A - Relative aircraft positions and velocities (encounter geometry)

1. “Blind-flying” risk [factors that affect

risk – no intervention]

(a) Horizontal and vertical

positions and closing angles

(b) Aircraft velocities and

accelerations

(c) Climb/descent rates and

accelerations

(d) Vertical path separation at

crossing point

With respect to UAV these criteria, especially b, c and d are

influenced by performance, handling quality, control laws as

well as by the overall design concept of the respective UAV.

UAV may differ considerably from air transport traffic.

In case of a relatively slow flying UAV on an air route,

continuous risk of collision from behind is present (refer to

2.0 “TCAS / ACAS”).



Date: 10.12.01page 110

A - Relative aircraft positions and velocities (encounter geometry) contd.

2. Pilot intervention – factors that

affect timely pilot detection and

correction

(a) Closure rate Reflects the relative geometry between an air vehicle and

the separation inflicting UAV and depends from the general

situation, the performance and other internal factors. For

example if the UAV is co-ordinated into normal IFR traffic or

does it use special procedures or special separation minima

(b) Relative bearings and aspects

angles in relation to cockpit

field of view restrictions, the

horizon

(c) Rate of change of the above

angles (zero for linear collision

courses)

(d) Aircraft attitudes and ban

angles

(e) Meteorological conditions and

background conditions,

including location of the sun

(affecting ability to perceive

other aircraft and their relative

distance, velocity, and

trajectory)

(f) Natural lighting conditions

(e.g., day, night, dawn, dusk)

(g) Threat aircraft size, skin

colour, and lighting

(h) Condensation trails

(i) Empty visual field

(j) Night accommodation

Reflect the ability of the pilot in an aircraft to detect/see

another aeroplane as well as to detect the loss of

separation by visual perception.

In IMC, the pilot has no “natural” vision outside the aircraft.

Currently upcoming in the civil air transport business is syn-

thetic vision (enhanced vision) for e.g. the final approach,

generated by light intensifying sensors or IR-Sensors.

The UAV operator of an UAV never has a direct visibility out

of his UAV but is restricted merely to sensing if this is

provided. However, sensing allows to draw up different

scenarios:

Worst case :

no sensing and no direct situational awareness

Best case :

In the most favourable case, the UAV operator has

available a sensor-suite, which gives in a 3 dimensional

combined display a far better situational awareness with

respect to weather, range and field of view/regard than

direct eye sight:

• 360° horizontal/vertical

• sensing independent from visible light by radar, IR,

light intensifying, and other sensors, may be borrowed

from military seeker technology (e.g. UV spectrum)

• range finding supplemental to radar (laser range

finder)



Date: 10.12.01page 111


2. Pilot intervention – factors that affect

timely pilot detection and correction

(contd.)

It must be fully understood, that the display for the UAV

operator must not give a real picture of other traffic and

obstacles, that means being like a vision system for

manned simulation. The display could show only

information necessary for the very purpose of collision

avoidance and others. The problem is the data link, the

capacity of which is limited. Sensor fusion and other tasks

must be done onboard to minimise data flow to the UCS.

On the ground, appropriate symbology will be processed

and displayed.

These techniques, in the research named some times

“synthetic vision” and envisaged as enhancement for

manned aircraft and UAV can also enhance the UAV

operation in unreserved public airspace with mixed IFR and

VFR traffic also in a high density environment. Furthermore

these comprehensive sensing techniques are the basis for

automatic collision avoidance with respect to all air traffic

and in consequence for a true autonomous and safe flight.

All air traffic comprises all sort of man made air traffic

(manned/unmanned aircraft down to ultra lights,

parachutes) as well as natural air traffic (bird strike risk).

On the other hand, “being seen and avoided” is essential in

the same way for VFR / IFR traffic, as long as a “naked”

human vision is involved. Certification requirement drafts

tend to address this fact by lighting and colour scheme. But

small and slender fuselages, as UAV have, are difficult to

acquire, even in bright colour scheme.

Remark: Giving UAV appropriate painting and lighting to

ease detection by aircrew is matter of certification

procedures and draft papers.

Though these techniques are ready to come, they are

not in the economic reach of the commercial air traffic,

no matter if manned or unmanned. With special respect

to UAV, the equipment mass and volume as well as

power consumption is of additional strong concern.



Date: 10.12.01page 112




(contd.)

(k) Party line

Party line (effect) is the ability to generate a mental picture

of the traffic situation merely by listening to the radio

communication between ATC and the respective air traffic

or between air traffic in the neighbourhood of the own

aircraft. Thus, situational awareness is enhanced. On the

other hand, excessive speech transmissions may degrade

human performance.

The upcoming data link communication will in principle

cause a loss of party line. The effect will be researched also

within CARE and should be checked with respect to UAV

operators of UAV.

Possible research issues are for example situational

awareness of UAV operator, needed to which extent; how

can party line be provided to UAV operators/operators; if

beneficial, skills needed by UAV operators to exploit party

line effect appropriately.

(l) Reliance on ground-based

surveillance and procedures

With respect to manned aircraft, this means that the crew in

an aircraft reduces vigilance, if they fly under radar

surveillance.

The UAV operator of an UAV has to rely in many aspects

completely on radar coverage. If other means of collision

avoidance are available these means can back up radar

coverage or complement radar coverage

Additionally the UAV operator of an UAV has to monitor the

flight status of the UAV to avoid deviations from the planned

and/or cleared flight path. (Like in ATC announcement,

automated procedures can be foreseen to detect small

deviations. Their sensitivity can be dependent from

airspace, e.g. higher in terminal area.



Date: 10.12.01page 113




(contd.)

(m) Cockpit workload, staffing,

automation, and procedures

(n) Flight crew training, skill,

teamwork

With respect to UAV, these items m deal with the whole topic of

MMI of the UCS and training of the respective crew to operate and

“fly” the UAV. These topics are partially addressed in the

certification of UAV and need further research, because the

operation in a civil airspace is not performed routinely by UAV

users until now.

Topics concerning the UCS with respect to ATC, MMI and

questions of training must be incorporated into the research

activities.

(o) TCAS/ACAS responsiveness,

affected for example by aircraft

bank angle

The influences of TCAS/ACAS responsiveness are

basically the same for manned an unmanned air vehicles.

The effects of size and form of fuselage of UAV must be

thoroughly checked for each type. It is assumed, that UAV

are equipped with the latest version of TCAS/ACAS in all

aspects.

3. ATC intervention – factors that

affect the probability of timely and

effective ATC intervention

(a) Air traffic service provided

(b) Climb/descent rate and

acceleration (affects ATC

computer projections)

(c) Horizontal velocity and

acceleration

(d) Turn rate and turn acceleration

(change in turn rate)

(e) Airspace complexity

(f) Traffic complexity and density

(g) Proximity to an airspace

boundary (e.g., SUA)

(h) ATC co-ordination (e.g.,

involving an aircraft in hand-off

or point-out status)

These items affect the probability of timely and effective

ATC intervention with respect to UAV too. Additionally a

delay factor may be expected due to data link

communication and lack of direct control capability of the

UAV operator of the UAV.

Due to proven ATC procedures no procedures will be

changed because of rare UAV flights. But UAV-flights

should be kept in mind in course of changes, e.g. to ADS-B

Furthermore it must be thoroughly checked, which classes

of UAV (mainly performance, manoeuvrability, MMI delay)

are cleared into which airspace – categories and under

which circumstances.



Date: 10.12.01page 114


3. ATC intervention – factors that affect

the probability of timely and effective

ATC intervention (contd.)

(i) Air traffic management tools

for reducing controller

workload and improving

controller intervention

capability

• Automated controller

planning tools including

trajectory projection, conflict

probe, and conflict

resolution.

• Automated out-of-

conformance alerts (3D and

may be 4D), which alert

ATC to any deviation of an

aircraft from its nominal

path.

• Controller display quality:

picture, information, and

presentation of information.

The automated planning tools or alerts should take the

presence of UAV into account. This begins with filing a flight

plan for each UAV flight, special transponder code and

direct data link between ATC and UAV operator.

On this basis, the automated tools should take into account

the performances of the respective UAV (coding filed with

the flight plan or/and down linked within the ADS-B

parameters, special criteria should be applied for the

automated tools).

Thus, for example, an alert could be given earlier than in

case of a manned aircraft.

Some research of the flight path accuracy must be done

with respect to ATM tolerances and separation. The same

is true for the whole topic of procedure design, especially

with respect to TMA procedures.

Principally 2 sets of data from an UAV can be exploited:

§ The surveillance data, gained by ATC, i.e. radar, or

ADS-B data

§ The relevant data (position, speed etc.) which are

exchanged between UAV and the respective UCS

(permission to exploit these set of data of military UAV

for civil ATC might be refused by a military operator).

By this procedure, relevant data of the UAV can be

gained without an explicit ADS-B requirement. This can

be helpful for the integration of UAV into the ATM.

However, the exploitation of the data by ATC needs

further research.

(j) Controller skill, training, and

teamwork

(k) Controller workload, staffing,

and procedures

A controller should not have to do other/different ATM-tasks

with respect to UAV then with respect to conventional air

traffic (e.g. controller should not be UAV operator of an UAV

when managing air traffic).

But the incorporation of UAV traffic will evoke changes and

need additional training of the controller.



Date: 10.12.01page 115


4. Aircraft reaction – factors that affect

aircraft reaction time in response to

a needed manoeuvre

(a) Aircraft performance (including

manoeuvrability)

(b) Pressure and density altitude

(related to aircraft performance

and atmospheric conditions)

(c) Speed (e.g., relative to stall

speed, available thrust, etc.)

The reaction time of a response to a needed manoeuvre of

an UAV may differ significantly from a civil air transport (or

executive jet), according to conceptual design,

performance, control laws etc. Additional reaction time may

be needed on the communication way from ATC via link to

the UAV operator and continued from the UAV operator to

the UAV.

Of additional concerns is the MMI of UCS and the concept

of control of the UAV. Refer also to A2m, n, cockpit work

load, flight crew training.

(d) Climb/descent rate

(e) Attitude and bank angle

(f) Proximity to terrain

See also item in ref. D 3 “Aircraft –

Aeroplane / Power plant” below

The task of flying an air vehicle can be divided in 3 portions

of different gain:

• short term attitude control (stabilisation)

• mid term velocity and position control (guidance)

• long term course control (navigation).

In a properly designed and certified General Aviation

aeroplane, all 3 tasks can be fulfilled by a pilot,

sophisticated aeroplanes (Commercial Air Transports) have

automatic flight control systems, auto pilots and fly to a

great extent “automatically”. But despite these aids, also in

most recent aeroplane designs, the pilot can use a hand-

wheel or stick and hand-fly the aeroplane directly. In most

cases, the pilot is aided by fly-by-wire and appropriate

control laws (care free handling), which exploit the utmost

distant areas of the flight envelope. Thus a pilot would

respond to an urgent advise by ATC or even by a

TCAS/ACAS alert. This immediate and quick response may

not be possible in an UAV control station or could take more

time due to several reasons.



Date: 10.12.01page 116


4. Aircraft reaction – factors that affect

aircraft reaction time in response to a

needed manoeuvre (contd.)

For UAV- systems (vehicle-data link-UCS) minimum

requirements criteria must be defined for reaction time,

comprising the whole sequence:

• initiation by ATC via data link to UAV operator

• UAV operator input via data link to UAV

• UAV reaction time, begin of requested manoeuvre

appropriate displacement, change of course etc. of

the UAV.

Sufficient reaction time can be assured by hand-flying in

combination with carefree handling or by setting auto pilots

with complete control authority available. Today, auto pilots

achieve for example roll rates of 5° per second in procedure

turns. This value is not suitable for any collision avoidance

manoeuvre, as mentioned before.

Remark:

Autonomous Flight is addressed separately, but must be

checked with respect to auto pilot rate limits. With respect to

TCAS/ACAS and ADS-B the remarks under chapter “Type

of airspace/controlled airspace in IMC” are valid too.

Excerpt from TCAS II Airworthiness Approval [21]

The TCAS II RA algorithms are based on the pilot initiating

the initial 0.25 g acceleration manoeuvre within

approximately 5 seconds. Pilot response is expected within

approximately 2 – ½ seconds if an additional RA is issued.

(The increase rate and rate reversal RAs are based on a

0.35 g acceleration manoeuvre.) Because of these

requirements and the rate limits of the auto pilots, all RA

responses must be hand-flown and not with the auto pilot or

auto throttles engaged.

To cope with the performances of the UAV certain

Resolution Advisories may be inhibited, no to exceed critical

limits.



Date: 10.12.01page 117

B - ATC rules and procedures, airspace structure

1. Hemispheric rules

2. Route structure, i.e., the use of

parallel or non-parallel ATS routes

and whether they are bi-directional

or uni-directional

3. Separation minima

(a) Horizontal

(b) Vertical

(c) How often values close to the

“official” separation minima are

used in practice.

These items describe a conventional airspace structure. For

civil purposes UAV may have to use this airspace structure

without disturbing the traffic flow. The new traffic

environment model of Eurocontrol is referenced on other

places, additional considerations concerning ATC

procedures are referenced at the end of B.

4. Flight planning

(a) Requirement to file flight plan

(b) Requirement to fly in

conformance to flight plan

(c) Requirement to cruise at

certain discrete altitudes –

Hemispheric rules

Mandatory filing of a flight plan can be found in almost alldrafts of UAV operating procedures in civil airspace. It mustcontain a hint that the respective vehicle is an UAV. Referto UCS. The flight planning of a civil UAV, and missionplanning of a military UAV (using civil airspace) mustcontain at least the same information concerning AIS asflight planning of a manned air vehicle, e.g. European AISData base, NOTAM etc. This data –base must containspecial information for UAV, if in the future it is found outthat info of this kind is to be spread (e.g. temporarilyrestricted air space for UAV, manned air vehicles only)should UAV operators or operators of UAV be informeddistinctly about other UAV operations / general informationabout UAV operation to all aviators.

In case of full data link loss the flight plan should addressadequate strategy for vehicle recovery.

An other topic of flight planning with potential effects to ATM

is the susceptibility of an UAV to weather influence, as

storms icing etc. These weather phenomena must be

incorporated into flight planning, tailored to the type of UAV

As for modern aircraft, especially military aircraft, the

planning of an UAV flight should contain detection of conflict

with detailed airspace structure and with terrain. So

planning errors could be minimised.



Date: 10.12.01page 118

B - ATC rules and procedures, airspace structure (contd.)

5. Requirement to obtain clearance

prior to altitude change

6. Positive control

7. Airspace complexity and flight path

geometry, including the following:

(a) Traffic demand pattern

(b) Number of aircraft at same

altitude

(c) Numbers and locations of

crossing tracks

(d) Amount of traffic operating on

opposite direction tracks

These items describe various ATC rules, procedures and

airspace structures. In the course of further research

including real time and fast time simulation, it must be found

out if the respective UAV operation can follow all these

current or future conditions. Some of the items are indirect

relation to an UAV operation

• diversity of traffic (7f)

• Take off of an UAV from a runway of a normal airport

will be time consuming (7h)

• Civil UAV operation will probably often be in

conjunction with special purposes and therefore

take place in TRA, SUA etc.(e.g. photo flight,

relay flight, environment control) (item 7i).

(e) Amount of traffic transitioning

altitudes

(f) Nature of the aircraft

population (i.e., the diversity of

traffic with respect to aircraft

performance and equipage,

such as the mix of various

speeds, climb performance,

and desired optimal flight

levels)

(g) Peak and average traffic

demands versus system

capacity

(h) Runway capacities and the

limitations of associated

ground services

• It must be checked, if UAV sustain the same

meteorological conditions as air transports or

executive jets (storms etc.). If this is not the case,

restrictions must be imposed and/or a certain among

of deviations from planned flight, caused by met

conditions, will be experienced. This will in turn lead

the higher ATC workload, traffic co-ordination effort

and may be emergencies of UAV (item 7j).

• Special airspace restrictions may be imposed

by the flight of civil UAV (relay station, environment

control etc.) and thus cause additional co-ordination

effort (item B10).

• Military operations in all aspects will be a great portion

of UAV traffic (e.g. B11).



Date: 10.12.01page 119

B - ATC rules and procedures, airspace structure (contd.)

(i) Any adjoining special use

airspace, airspace usage, and

types of activities including the

civil/military mix

(j) Regional meteorological

conditions (e.g., the

prevalence of convective

storms, etc.)

(k) Designated airspace

classification

8. Flow management capability (ability

to control traffic input to ATC)

(a) Strategic air traffic flow

management

(b) Tactical air traffic flow

management

(c) Ad hoc ATC “in trail”

restrictions or enhancements

(d) Procedural restrictions (e.g.,

by local operating procedures).

9. Special airspace restrictions

(a) Restricted airspace

(b) Special use airspace

(c) Traffic flow restrictions

(d) Noise abatement restrictions

10. Special situations

(a) Air shows(b) Other aviation-intensive events

(e.g., Olympic games)(c) Military exercises

(d) Formation flight

(e) Backup procedures

Special attention must be given to the whole complex of

procedure design. The most significant concern is given to

the terminal procedures for departure and arrival (SID and

STAR). Given, that the UAV is taking off and landing on an

airport together with GAT and commercial air transport, SID

and STAR or at least portions of it are the flight segments,

where traffic is mixing closely making effects of traffic

diversity show up most distinctly causing congestion and

delay. It is also the segment, where separation and

sequencing is the most demanding task. Caused by the

same effect, small single engine aircraft are banned from

several airports. The design guides and values for terminal

procedures must be reviewed as well as the performances

of the UAV-classes. Eventually the proven or new complex

procedures, possible due to P-RNAV and necessary due to

noise abatement and other environmental considerations,

cannot be followed adequately by UAV classification with

this respect should be available. The following table shows

the aircraft approach categories A – E according to the

speed. If the task of separating and sequencing the air

traffic cannot be fulfilled, the safe, orderly and expeditious

flow of air traffic finally is endangered by the UAV.

Eventually new design guidelines and finally procedures

must be generated for the UAV, given that the UAV are

landing and taking off according IFR. This assumption is a

reasonable one as long as the usage of civil airports is

assumed. Eventually different STAR and SID have to be

foreseen according to the respective performance of UAV.

An appropriate classification with this respect should be

available. The aircraft approach categories A – E according

to the speed are shown in the table at the of this appendix.



Date: 10.12.01page 120

C - Communication capability

1. Direct controller/pilot voice

communication (VHF/HF/SATCOM)

2. Indirect controller/pilot voice

communication (HF)

3. Controller/pilot data link

communication (CPDLC)

4. Controller/controller voice and

automated data link

communication, both inter and intra

ATS unit(s)

5. Data link between ground ATC

automation systems and aircraft

flight management computers

6. System availability, reliability, and

capacity

7. Backup systems and procedures

Communication Capability

With respect to UAV the communication capability differs

from manned air vehicles. In principle, 3 data links exist with

respect to ATM.

§ Data link between UAV and UCS (UAV operator)

§ Data link between UCS (UAV operator) and ATC. It

must be researched if pure data or pure voice alone are

sufficient. But given voice as most direct communication

and data link as valuable basic communication, both

should be available.

§ Surveillance data link between UAV, other air traffic and

ATC in an ADS-B-environment.

It should be researched if the data link from UAV to ATC

can contain also some information concerning technical

status of UAV.

The reporting of technical problems of a manned aircraft,

having consequences to ATC/ATM, is done by the aircrew

direct to ATC. In many cases, ATC knows about the

problem and actions before the ATC surveillance

(eventually automated) shows deviations or other problems.

Technical problems of an UAV are down-linked to the UCS

and afterwards passed over to ATC by the UAV operator.

This may be time consuming and cause considerable

delays.

The data links are vital for safe UAV operation and safe

UAV operation in civil airspace, therefore redundancy or low

MTBF are of great importance. (This is also reflected in at

least some of the certification paper drafts.)

Data link between ground ATC automation and aircraft flight

management computers will be replaced by data links from

the UAV as well as from the UCS to ATC automation

system (refer to C5).



Date: 10.12.01page 121

C - Communication capability

7. Backup systems and procedures

(contd.)

In the mid-term future and in the course of ADS-B technical

pre-conditions will be given, that ATC gains some influence

on the control of aircraft in some severe cases of

emergency. A clearance is issued by ATC, seen and

confirmed via CPDLC by the pilot and after this procedure

passed over automatically into the FMS. FMS sets auto

pilot appropriately and aircraft proceeds as cleared. The

same far future procedure can be planned for a

communication between ATC and UAV operator.

By this procedure, errors in understanding the clearance,

interpret the clearance or set a FMS/Auto pilot can be

avoided in case of air vehicles, no matter if manned or not.

D - Aircraft

1. Certification standards

(a) Airframe

(b) Power plant

(c) Systems

2. Maintenance [including manuals]

(a) Airframe

(b) Power plant

(c) Systems

Certification standards and maintenance procedures are

within the scope of appropriate drafts for UAV, also UAV

using civil airspace. Airframe inertia

3. Aeroplane/power plant (applies

for normal operation and

abnormal operation, e.g. loss of

engine, or failure of some

aeroplane systems)

Performances and manoeuvrability of UAV may cause

problems if deviating significantly from other air traffic. This

was discussed previously under item A4A



Date: 10.12.01page 122

D - Aircraft (contd.)

(a) Speed and altitude envelope of

the aeroplane type (This factor

may contribute to exposure

frequency in cruise operation

in a given airspace.)

(b) Climb and descent profiles

(speed/thrust/altitude profiles)

[may affect exposure

frequency in climb and

descent]

(c) Manoeuvre response

capability (e.g., to a controller

or TCAS/ACAS alert), such as:

• Engine spool up time

• Airframe inertia

• Rate of climb or descent

• Level acceleration /deceleration

(d) Aeroplane dimensions and

wake vortex profile

RVSM and other items as parallel runways draw up

possible interaction with wakes also en-route. This is the

same for UAV, especially if overall layout gives a higher

sensitivity

4. Aeroplane systems factors

(a) Navigation Sensor complement

• ADF

• VOR

• DME

• IRS (newer, strap-downinertial reference systems)

• INS (older, gimballedinertial reference systems)

• Loran

• Omega

• Satellite-based systemssuch as GPS, GLONASS

• Other



Date: 10.12.01page 123


4. Aeroplane systems factors (contd.)

(b) Navigation systems

1) Navigation computersystems

2) Other, like-capability areanavigation (RNAV) systems(on other aircraft)

3) Navigation SystemPerformance§ Required navigation

performance (RNP)

§ Typical and non-typicalperformance (e.g.,MASPS/MOPS; RTCASC-181 documents)

§ Time-keeping accuracy§ Reliability/availability

§ Integrity§ Effects of more accurate

navigation

“Unfortunate”interaction of pilotblunder/altitude miss-assignment and moreaccurate navigation(i.e., a blunder wouldbe more likely to putone aircraft right ontop of anotherbecause of the moreaccurate horizontalnavigation providedby GPS).

In principle, all items apply to UAV (except the smaller

range of navigation sensors, UAVs will have only GPS/INS

in an UAV). Equipment of this sort has an inherent

capability to fulfil all future requirements of P-RNAV. On the

other hand, it must be checked, that the intended air route

is approved for an IFR flight based on P-RNAV only and

that the respective certification requirements allow IFR flight

with P-RNAV only.

Navigation System Performance must fulfil the

requirements for civil airspace and the RNP concept

established by the national authority. That means in turn,

these requirements must be reflected in the airworthiness

requirements for the UAV

[24] addresses the navigation performance for track

keeping accuracy.

It must be discussed, if for safety reasons higher

requirements of accuracy are necessary, which allow an

immediate detection of deviations by automated ATC

systems. The technical feasibility must be researched as

well.

(c) Communications capability

1) Voice communicationssystems

A) Commercial aircraft

- Required

communication

performance

- VHF systems (direct)

- HF systems (indirect)

Communication capability of data links is discussed in the

previous chapters. ACARS is not needed by UAV, it’s

function is performed by the data link between ATC and the

UAV operator. Between ATC and UCS voice

communication is absolutely necessary, fixed lines may

complement radio communication.



Date: 10.12.01page 124


4. Aeroplane systems factors (contd.)

B) Military aircraft

C) General Aviation and

other aircraft

D) UHF

E) SATCOM

(communication via

satellite)

2) ADS-B3) ACARS

(d) Surveillance capability

1) Required surveillanceequipment performance

2) Air-ground transponder

A) Mode C transponder

B) Mode S transponder

Mode S with appropriate

level and surveillance

degree canal

C) Mode A transponder

3) TCAS/ACAS (Traffic Alertand Collision AvoidanceSystem/Airborne CollisionAvoidance System)

4) Advanced TCAS/ACAS

5) Automatic DependentSurveillance (ADS)

6) Cockpit display of aircrafttraffic information (CDTI)

With respect to UAV and as discussed earlier, TCAS/ACAS

is not the solution, only contribution to the problem.

Beside providing independence from primary radar echoes,

Mode-S-Transponders form together with TCAS/ACAS-

equipment the basis for collision avoidance. Mandatory

introduction of several levels of Mode S data link capability

is already planned, Mode S may also become the data link

for the future ADS-B.

TCAS/ACAS equipment and ADS-B provide independent

data link capability between air vehicles and between air

vehicles and ground. ADS-B is furthermore the basis for a

free flight environment, envisaged in the ATM 2000+

strategy.

ATM 2000 + provides direct routing, responsibility sharing

between ATC and aircrews (in the future also UAV

operators?), de-confliction and short term collision

avoidance.

The CDTI is the display of all the ADS-B data. TCAS/ACAS

provides a first step for a sense and avoid capability but is

by far not sufficient. VFR traffic in the controlled airspace is

normally equipped with TCAS/ACAS and some IFR traffic is

not equipped too.



Date: 10.12.01page 125

Latest TCAS/ACAS equipment offers greater detection

ranges, nearing ADS-B, incorporation of EGPWS/TAWS

(no resolution advisory which inflicts with terrain). Derived

from military equipment (e.g. ETCAS) the elliptical warning

box of TCAS/ACAS can be given a spherical form, so also

warning from behind can be given.

With respect to TCAS/ACAS, the performances of the

respective UAV must be matched with the TCAS/ACAS

models, eventually capability must be restricted because

resolution advisories cannot be followed.(Refer to A4.)

Generally the procedures, software, algorithms etc. must be

checked with respect to UAV operation. TCAS/ACAS and

ADS-B do not contain any automated collision avoidance.

All TCAS/ACAS advisories must be linked at least to the

UAV operator and followed by his/her action (refer to item

A4 concerning reaction time of an UAV).

(e) Backup systems and procedures

E - Ground/Satellite systems: Surveillance and Navigation

1. Surveillance capability

(a) Procedural dependent

surveillance

1) Content of pilot positionreports

2) Reporting intervals

(b) Automatic dependent

surveillance (ADS)

1) Basic update rate

2) Display accuracy; controller

display target position error

3) ADS contracts (e.g.,

increased reporting rate by

triggering events)

4) Sensor accuracy

5) System reliability

In principle all items of Ground/Satellite systems for

surveillance and navigation are of importance for UAV

operation.

In comparison to manned air vehicles the importance of a

single item may be changed considerably.



Date: 10.12.01page 126

E - Ground/Satellite systems: Surveillance and Navigation

1. Surveillance capability (contd.)

6) System availability

7) End-to-end

communications time

capabilities

(c) System coverage Independent

surveillance (radar)

1) Type of sensor (primary or

secondary)

2) Coverage area

3) Processing and associated

delays

4) Accuracy of measured

position after processing

A) Radar registration error

(Mosaic)

B) Slant-range error for

non-Mode C equipped

aircraft

5) Update rate

6) Display accuracy (error)

7) System reliability

8) System availability

9) Backup systems

2. Performance

(a) Accuracy

1) Automation-induced errors

(b) Reliability/availability

Concerning E2 Performance, the automation induced errors

must be looked over, because more automation and links

takes place from side of the UAV as direct input in ground

systems automated systems.



Date: 10.12.01page 127

E - Ground/Satellite systems: Surveillance and Navigation (contd.)

2. Performance (contd.)

(c) Integrity

1) Automation-induced errors

2) False positives

3) Missed events

(d) Equipment outage

1) Backup systems, including

power

A) Availability

B) Reliability

C) Integrity

2) Backup procedures

(e) External interference

1) Natural

2) Human

A) Sabotage

B) Spoofing

C) Jamming

Processing, data trans-flight, and

associated delays (e.g., delay between

acquisition of a signal and the display of

the information)

The external performance (natural and human) is of special

importance, because a malfunction may cause

controllability problems of the UAV



Date: 10.12.01page 128

F - Human performance

1. Flight crew performance/skill

(a) Monitoring/situational

awareness

(b) Crew co-ordination and

communication/Cockpit

Resource Management

(c) Controller/Pilot

communication/co-ordination

(also see section F.2.c. of this

outline)

(d) Response time

(e) Movement time

(f) Crew workload and vigilance

(g) Human error/human reliability

(h) Interaction with

hardware/software

automation/assistance

1) Displays

2) Warnings/advisories

A) TCAS

B) CDTI

(i) Certification standards

(j) Training

(k) Operator procedures, manuals

(l) Corporate culture

Concerning Human Performance/skill of a UAV operator, no

broad experiences seem to exist. The procedures

concerning error management in the cockpit may have

changed for a UAV operator.

Some facts can be derived from aircrew human research.

As mentioned before, the entire UAV system including UCS

must be considered



Date: 10.12.01page 129

F - Human performance (contd.)

2. Air Traffic controller

performance/skill

(a) Monitoring/situational

awareness

(b) Decision making

(c) Controller/pilot communication

/ co-ordination

(Also see section F.1.c of this

outline)

(d) Controller/controller

communications and co-

ordination

(e) Controller Response Time

(f) Controller Workload

(g) Interaction with

displays/automation/ decision

aids

1) Displays

2) Automation

3) Decision Aids

4) Warnings/advisories

A) Flight path prediction

B) Conflict probe

(h) Controller errors

(i) Training

(j) Corporate culture



Date: 10.12.01page 130

G - Environment

1. Visibility

(a) Day/night/dusk/dawn

(b) Ceiling

(c) Sun position

(d) Clouds

(e) “Background” (i.e. against

which pilot is to locate other

aircraft)

2. Adverse weather, storms

3. Turbulence, wind shear

4. Special problems (e.g., volcanic

ash)

5. Wake vortex (may cause turbulence

or engine problems for following

aircraft at same or lower flight

levels)

The visibility is of importance only in a line of sight operation

Adverse weather and turbulence must be sensed by the

UAV in a predictive rather than reactive manner and down-

linked to the UCS. From there, a circumnavigation can be

initiated when cleared by ATC. ATC can support the UTC in

the same manner as a manned aircraft by the ground bases

weather radar and by PIREPs (pilot reports of aircraft in the

vicinity of the UAV).

Safety concerns concerning wake vortex are the same as

for manned aircraft, especially taking into account the small

sized UAV in mixed traffic with airline transports. RVSM

broadens the safety concerns into the enroute segment of a

flight.

These factor pose also special difficulty during autonomous

flights.

Table 13-1 - Factors for Separation Safety

Categorisation of manned Aircraft according to their Approach speeds (ICAO)

The following ICAO table indicates the specified range of handling speeds (KIAS) for each

category of aircraft to perform the manoeuvres specified. These speed ranges have been

assumed for use in calculating airspace and obstacle clearance requirements for each

procedure.

This table should be used as preliminary guideline for approach categorisation of UAVs.

However, if further investigation or development indicates that other categorisation are more

adequate for UAV, new tables could be used accordingly.



Date: 10.12.01page 131

MAX SPEEDS

for Missed ApproachAircraft

CategoryVat

Range of

Speeds for

Initial Approach

Range of

Final

Approach

Speeds

MAX SPEEDS

for Visual

Manoeuvring

(Circling)Intermediate Final

A <91 90/150 (110*) 70/100 100 100 110

B 91/120 120/180 (140*) 85/130 135 130 150

C 121/140 160/240 115/160 180 160 240

D 141/165 185/250 130/185 205 185 265

E 166/210 185/250 155/230 240 230 275

Table 13-2 - Categorisation according Approach Speeds for Manned Aircraft

Notes:

1) Vat Speed at threshold based on 1.3 times stall speed in the landing configuration at maximumcertified landing mass.

2) * - Maximum speed for reversal and racetrack procedures.

3) Category E contains only certain Military Aircraft.



Date: 10.12.01page 132

14 Appendix G - Detailed Description of Data Link

The first part of this Appendix contains the basic description of data links for UAV and the

second part presents details concerning data link of some selected UAV.

14.1 Description of Data Link

The types of UAV data links used and their requirements highly depend on the objectives of

the intended operation. The main characteristics are the operational range and the

flight/mission control capabilities as well as the means deployed to increase availability and

robustness of the data link.

Currently the UAV use three types of data-link established between the UAV and the UAV

control station (UCS):

• flight and task control data-link

• system monitoring data-link

• task data-link

For use of UAV in a commonly used airspace there should additionally be a direct link

between UAV and ATC, for example voice communication, and between UAV and other air

traffic, either manned or unmanned.

14.1.1 Function of Data Links:

The accomplishment of UAV-Operations always requires a communication channel between

the operating UAV and a UAV control station (UCS). The connection is realised via a data

interface, whose characteristics depend on the UAV task objectives. The communication

between the controlling station and the UAV can be established:

• directly between the two entities

• via relay stations (ground relay stations, other UAV, aircraft or satellites)

• within combined operations (partial use of different data transfer resources within a co-

ordinated deployment of various aircraft and controlling stations e.g. tactical combined

missions)



Date: 10.12.01page 133

The data-link types of current UAV, seen from the applications side, can be categorised as

follows:

(a) Flight and Task Control Links

Flight guidance and the control of the task platform (e.g. activation and alignment of

sensors) require an up-link from the UCS to the UAV. As the data-link to the UAV might

be lost during the operation, it is necessary that omni-directional antennas (di-pol) are

used for the flight and mission control data-link; otherwise it will not be possible to

regain the control over the UAV after loss of the data link.

The main characteristics of the flight and mission control information are:

• Small amount of data to be transferred,

• Main data transfer is up-link (from UCS to UAV),

• Need for high protection against manipulation and transmission error due to the

high malfunction risk.

The data to be exchanged on the flight and task control link can be categorised as

follows:

• Flight control data (Remote control of the UAV by the UCS, up-link)

• Position data (3-dimensional position of the UAV, down-link)

• Auxiliary data (including further extensions of the data format, probably up- and

down-link)

The kind of the data, with respect to for example data amount or transfer rate, requires a

duplex data-link. Since data which applies to the Flight Control System (FCS) of the

vehicle is flight safety related for many applications, the encryption of the up-link is

mandatory. Based on a variable duration of a mission, dynamic re-keying is

recommended for this kind of information / data (changing valid keys during flight

operation).

Many requirements on functionality, performance and safety for this type of data-link are

determined by the UAV grade of autonomy. Many of the current and future UAV designs

show an increasing grade of autonomy, including capabilities for a fully autonomous

flight. The required level of autonomy influences the design of the data link, especially in

terms of real time characteristics, the kind and degree of link protection and finally the

link availability. Also the data amount to be exchanged depends on the level of

autonomy.



Date: 10.12.01page 134

With fully autonomous systems it might be significantly reduced.

As the amount of data exchanged for flight and mission control tasks will be relatively

small and Omni-directional antennas have to be used, narrow banded channels with

data rates between 1 kilobit per second (Kbps) and several 10 Kbps are regarded to be

adequate for this type of data-link.

As several UAVs may be controlled by the same UCS, a light multicast scenario should

be assumed:

1 UCS is responsible for n UAV. The different UAVs can be selected using different

addresses (using the same frequency); for the down-link radio connections a specific

access scheme to the radio link has to be implemented (to avoid garbling problems), e.g.

using TDMA or time slotted channel access.

To allow that UAVs may be handled by ATC as a "normal" aircraft, the differences to

manned vehicles should be limited to a minimum. That means that normal voice

communications between ATC and UAV must be possible. In this case a voice

communication between ATC and UAV has to be extended backwards to the UCS

(including the voice stream into the flight and mission control data-link). This needs

about 3 - 10 Kbps.

(b) System Monitoring Links

The control station of any operating UAV requires the continuous availability of the

precise aircraft position, the flight status (e.g. speed, altitude/height), the current

technical status and the operation status. Characteristics of system monitoring data

are:

• Small to medium amount of data to be transferred (depending on whether the

information is updated continuously and frequently or on request),

• Mainly unidirectional data transfer (down-link), except acknowledgement

messages,

• Minor need for protection (only against loss and error)

As with the flight and control mission information, the data amount to be transferred for

system monitoring is comparatively small.

(c) Task Data Links



Date: 10.12.01page 135

Presently almost all UAV are designed for civil or military object search or surveillance

tasks. To accomplish these tasks they are equipped with electro-optical sensors and/or

radar systems. These sensors typically produce either raw data streams or processed

data streams in the multi megabit (Mbit/s) range. For example uncompressed high

resolution colour video streams require a bandwidth up to several hundred MBit/s.

UAVs have two options to treat such data streams:

1. Send the data streams unchanged as raw data. This requires broadcast links

supporting the individual sensor time behaviour (transient data, synchronous

streams, etc.)

2. Pre-process the raw data streams on board to minimise the data amount to be

transferred and to de-couple the timing requirements of the physical sensor data

stream from the significant information it contains. A typical method is data filtering,

which is the extraction of significant information out of the raw sensor data. This

method requires high processing capacity in the UAV system. Another method is

the compression of the raw or processed data stream, which is often combined

with the data filtering method to achieve optimal results.

The main characteristics of mission data links are therefore:

• High to very high amount of data to be transferred,

• Data transfer normally down-link,

• Measures to guarantee the required throughput for raw data transfers. Additional

measures against bit errors are required at least for pre-processed data. Link

reliability is an important factor for successful and safe operation.

Task data-links normally have to operate in the same geographical ranges as the flight

control data links. With the required bandwidth it is not possible to use omni-directional

antennas, but highly directed ones (antenna opening angle about 1° - 2°).

In any case of operation (either the UAV is sending down-link directly to the UCS or via a

relay (also UAV based)), the directional antennas have to be aligned precisely to the

remote antenna. Therefore exact position information must be available in all three

dimensions. Based on the operational range and the opening angle, the position

accuracy must be at least 30 meters.

Based on the flight pattern of the UAV, there might be a requirement to rapidly adjust

the directional antenna in all directions. This may be achieved only by active antennas

and to support 360° redirection and by multiple antennas at the UAV.



Date: 10.12.01page 136

14.1.2 Characteristics of Data Links

The essential operational characteristics of data links are:

(a) Link distance

Link distance is the maximum distance between a UCS and the vehicle at which a data

link is fully operational. The maximum distance is determined by technical features like

the chosen operating frequency, the antenna type, the signal processing capabilities

and by environmental influences like the given geographic and climatic conditions. In

general, data links are classified in ”Line of Sight” (LOS) and ”Non Line of Sight”

(NLOS) systems. The classification depends on the chosen operating frequency. The

typical operational ranges for today’s ground to UAV links are between 30 and 400 km.

The most important parameters determining the range of a NLOS system is the

transmitting power. On the other hand, increasing transmitter power introduces other

problems concerning for instance the power supply budget. LOS systems require relay

stations to get over the line of sight barrier. Relay stations can be installed on the

ground, on other aircraft or on satellites.

(b) Link performance and quality

The capability of a data link to support the characteristic data requirements of certain

applications is expressed by performance and quality parameters. Typical parameters

are:

- bandwidth / data rate,

- transfer delay and its variation for real time data support,

- link budget (relation of the transmitter power and the noise power at the receivingend).

Additionally the capability of a data link is determined by its communication mode and

its link organisation. Data links are designed to operate in simplex, semi-duplex or in

duplex mode. While simplex is strictly unidirectional, semi-duplex allows the non-

simultaneous use of one link in both directions. The duplex communication mode

allows simultaneous data transfers in both directions, which is often realised by two

independent channels of opposite direction. In case of many different and complex

data streams to be transferred, the link organisation itself is another important factor for

link performance and quality. Link organisation means the provision of a flat or

hierarchical structure of logical transfer paths, to support the individual need of the

different data sources.

(c) Link protection



Date: 10.12.01page 137

Link protection has the task to increase the link availability to guarantee sufficient

communication exchange between an UAV and its controlling entity at any time. The

quality of all data links is exposed to environmental or self implied conditions. The links

of UAV with military tasks are additionally threatened by hostile jamming. To cope with

these influences, data links are often equipped with very complex and expensive

protection features. Well known protective features are:

- error robust coding techniques (redundant codes with error detection /correction),

- error robust protocols (e.g. handshaking and retry),

- minimisation of the electromagnetic exposure of jammers (e.g. by directed ornarrow beam antennas),

- frequency hopping methods,

- spread spectrum techniques (spreading the signal’s power spectrum beforetransmitting and compressing after reception),

- intelligent signal processing to eliminate selectively known jamming patterns.

(d) Data protection

Beside the link protection, many applications require their information contents to be

protected against intentional counteractive actions. This could also be important in

times of increased level of security due to terrorism threat. Typical threats are:

- Eavesdropping:By monitoring the communication, reconnaissance and telemetry data arediscovered by the wrong party. A result for example could be, that one could findout the remote-command mechanisms and is able to control the UAV. To protectthe information confidentiality, data are coded by using cryptic algorithms.

- Information corruption:The integrity of data transferred is compromised by unauthorised deletion,insertion, modification, reordering, replay or delay. The more an attacker knowsabout the UAV data semantics (see Eavesdropping) , the more specific andefficient manipulation actions can be applied. Methods to prevent compromisingdata integrity is the use of checksums and hash codes together with crypticalgorithms.

- Masquerade:An unauthorised entity pretends to be the authorised communication partner (e.g.ground control station, ATC, tactical station). For example if the masqueradeattack is successful, the UAV can be controlled by persons with definitively otherintentions. Typical countermeasures against such threats are the introduction ofproper authentication procedures between all partners, willing to communicateand the introduction of strict access control procedures.

There are many other intentional and unintentional threats to the whole UAV operation

(e.g. unauthorised access). Efficient information protection requires the inclusion of

security means in the design of the technical functions and operational / ATC



Date: 10.12.01page 138

procedures. As a first step typically a security analysis is performed over the whole

system (all entities involved direct or indirect in the data exchange of the UAV operation

have to be considered and evaluated)

Derived from the fundamental requirements, criteria with possible parameters, among others,

are listed below to describe the selected data links from the technical point of view:

• Link Application

• UAV Flight and Mission Control

• Platform/System Monitoring

• Environment Perception (Reconnaissance, target acquisition, etc.)

• Operating Frequency Range/Bandwidth

• HF: 1-30 MHz

• VHF/UHF: 30-1000MHz

• L-/S-Band: 1-2 Hz

• C-Band: 5 GHz

• X-Band: 10 GHz

• Ku-Band: 15 GHz)

• Signal modulation / coding

• amplitude modulation (AM) / analogue

• frequency modulation (FM) / analogue

• amplitude shift keying (ASK) / digital

• frequency shift keying (FSK) / digital

• phase shift keying (PSK) / digital

• Communication Mode

• simplex

• semi-duplex

• duplex



Date: 10.12.01page 139

• Data Rate

• Low Rate (Data rates typically transferable via HF): < 30 Kbps

• High Rate (All link protection schemes possible): < 1 Mbps

• Broadband: > 1 Mbps

• Link Range

• Line of sight (LOS)

• Non line of sight (NLOS)

• Antenna Type e.g.

• Guided Narrow Beam


• Link Protection e.g.



• Channel coding

• Error detecting/correcting codes

• Antenna characteristics (e.g. guided narrow beam)

• Transport securing protocols

• Data Security e.g.

• Authentication

• Integrity / Confidentiality

• Encryption

• Link Types

• The link-types are divided in

• short wave

• micro wave

• satellite

• analogue



Date: 10.12.01page 140

• digital

• ApplicationFor the application type three abbreviations are used:

• TC: Tele-command

• TM: Telemetry

• TV: Television

• Operating Frequency Range

• HF: 1-30 MHz

• VHF / UHF: 30-1000MHz

• L- / S-Band: 1-2 GHz

• C-Band: 5 GHz

• X-Band: 10 GHz

• Ku-Band: 15 GHz

• Antenna Type

• Narrow Beam


• Link ProtectionThere is a wide variety of possible link protections, some are listed below:

• Redundancy


• Directed narrow Beam Antennas


• Channel Coding

• Protocols

• CRC

• Data ProtectionThere is a variety of possible data protections, some are listed below:

• Encryption

• Authentication



Date: 10.12.01page 141

15 Appendix H - Preliminary Table of Failure Modes

This appendix contains the Failure Mode Table as described in chapter 2.6. It should be

stressed, that the entries in this table are preliminary only and need to be discussed with all

kind of experts involved in the integration of UAV in ATM. Furthermore the entries are only

made for a few selected failure modes to illustrate the Failure Mode Table and the respective

entries.



Date: 10.12.01page 142

FUNCTION FAILURE MODE FLIGHTPHASE

OPERATIONAL CONSEQUENCES HAZARD DESCRIPTION (ATM-VIEW) SEVERITYCAT.

UAV is still on ground - Slight increase in workload- Slight risk of infringing safe separation

(after possible go-around by otheraircraft)

4Take Off

UAV is already airborne - Enormous increase in workload- High risk of ground hit in populated area

1

Altitude is not sufficient for gliding in safearea

- Enormous increase in workload- High risk of ground hit in populated area

1Departure/ Climb

Altitude is sufficient for gliding in safe area - Significant increase in workload- Significant risk of infringing safe

separation- Possible risk of collision- Possible risk to human, animals and

environment

2

Cruise UAV is unable to maintain altitude - Enormous increase in workload- High risk of infringing safe separation- Medium risk of collisionNote: UAV performs emergency descent,traffic has to be co-ordinated immediately

2

Altitude is not sufficient for gliding in safearea

- Enormous increase in workload- High risk of ground hit in populated area

1Descent /Arrival



environment

2

Engine Power Total Loss

Approach /Landing



environment

2



Date: 10.12.01page 143

FUNCTION FAILURE MODE FLIGHTPHASE

OPERATIONAL CONSEQUENCES HAZARD DESCRIPTION (ATM-VIEW) SEVERITYCAT:

UAV continues take off - Significant increase in workload- Significant risk of infringing safe

separation (UAV might have to followcontingency procedure, airspace has tobe cleared)

3Engine Power Partial Loss Take Off

UAV aborts take off - Significant increase in workload- Significant risk of infringing safe

separation (landing traffic might have toperform go around, sequence has to bere-structured)

3

ALL Loss is notified, UAV follows pre-plannedroute

- Significant increase in workload- Significant risk of infringing safe

separation- Possible risk of collision

3UAV control data link Total loss

ALL Loss is notified, re-routing for certainreasons is necessary

- Enormous increase in workload- High risk of infringing safe separation- Medium risk of collision

2

Table 15-1 - Preliminary Table of Failure Modes

Severity Category 1: AccidentsSeverity Category 2: Serious incidentsSeverity Category 3: Major incidentsSeverity Category 4: Significant incidents



Date: 10.12.01page 144

16 Appendix I - Hand-Over and Border Crossing

Assumed that co-ordinated and separated traffic will be manged by ATC, regulations for

transition will be performed under oberservation and control of ATC. Therefore, in the table

below, the procedures are listed for co-ordination into or out off controlled airspace

respectively SUA. Due to the effort for integration into uncontrolled not reserved airspace it

may be assumed additionally, that the transition of the first UAV operations will be between

controlled airspace and SUA.

From

To

Controlled Uncontrolled Special use

Controlled Radar

Handover

Cancellation of IFR

or

pending until re-entry

Radar

Handover

Uncontrolled Radar

Recovery

- Radar

Recovery

Special use (SUA) Radar Handover

or

Radar Recovery

Cancellation of IFR

or

pending until re-entry

Radar

Handover

Table 16-1 - Regulations for Transitions

Notes:

• Valid for aircraft under positive Radar control; i.e.

- IFR traffic

- VFR traffic which is controlled by ATC

• For VFR traffic not under Radar control the transitions are performed as VMC transition

(might include Flight Information Service with handover to adjacent FIS agency).



Date: 10.12.01page 145

The procedures for handover of UAVs between different air space categories must be

defined according rules of the air.

Border crossing as well as the right for international flights is common praxis in the European

and world wide air traffic.

The same status must be envisaged and finally achieved for the operation of UAV. This

comprises harmonised certification rules and operating procedures including trans-European

ATM as well as legal regulations for commercial operation of UAV.

Within Europe and also world wide, the preconditions for ATM and also ATC are varying to a

considerable extent. This comprises among others the capability for radar surveillance and

associated airspace structure as well as ground based NAVAIDS and ground infrastructure.

With respect to border crossing, it must be assured, that all necessary preconditions, defined

within the future regulations for certification, operation and ATM with respect to UAV

operations are fulfilled in all countries concerned.



Date: 10.12.01page 146

17 Appendix J - Autonomous Flight

It must be fully understood, that automatic, autonomous flight of an aircraft is technically

feasible without pilot intervention from the ground, including take off and landing. (An other

question is, if the purpose of the flight can be achieved in a fully autonomous manner, but

this is not a matter of ATM). The real question is, if the integration into the air traffic is

feasible under the following conditions:

• No continuous command and control by an operator

• Autonomous decision making of the UAV unit concerning the pre-planned flight or re-planning (weather, technical problems, de-confliction, collision avoidance etc.)

• Autonomous flight in all airspace categories

These topics will be left mainly to detailed follow-on-studies, may be within CARE. It must be

researched, which degree of autonomy is necessary and / or desirable and/or possible for

UAV operation in the different categories of airspace.

In the following part, a short overview is given over possible degrees of autonomy (Autonomy

State). The conditions of primary guidance and control or supervision by a operator /

commander and the conditions concerning ATC are briefly addressed. All intermediate states

between the referred Autonomy States 1 to 4 are possible, depending on operation concept,

equipment of the whole system (vehicle, UCS, MMI etc). In addition, different degrees of

background supervision may be imposed for safety reasons to the primary operational

concept, but this fact is not separately addressed in the overview.

After the following overview, the different Autonomy States are described in a more detailed

manner.



Date: 10.12.01page 147

Drones Autonomy State 1No autonomy

Autonomy State 2Autonomousmanoeuvring

Autonomy State 3Limited AI pilotavailable

Autonomy State 4Fully autonomous AIPilot available

4-dimensional flightpath

preprogrammed preplannedpreprogrammed

preplannedpreprogrammed

partly autonomousrouting possible

autonomous routingpossible

Operator

• presence for safety continuous guidanceand control

as State 1 continuoussupermission partlyguidance and control

only safety back up

• possibility ofinteraction

only launch/recovery, if carefree handling as State 1 possible as in otherStates

only safety back up

• necessity tointeract

only via FTS, if in all cases in all cases but limitedautonomousmanoeuvring available

reduced necessity only safety back up

AI-Pilot

(Artificial Intelligence)

No No No Limited AI pilotavailable

Full AI pilot available

ATC

• presence/activity surveillance, if continuous contact tooperator

continuous contact tooperator

continuous contact tooperator and AI pilot

continuous contact toAI pilot (and operatoras safety back up)

• possibility ofinteraction

request or trigger FTS by advise to operator by advise to operator by “advise” to AI pilotand operator

by advise to AI pilot(safety back up gpilot)

Table 17-1: Level of Autonomy



Date: 10.12.01page 148

17.1 Drones

4-dimensional flight path preprogrammed (not changeable after

launch)

Operator

• presence for safety

• possibility of interaction only launch and recovery, if

• necessity to interact only via FTS

AI-Pilot No

ATC

• presence/activity only surveillance, if continuous contact to

operator

• possibility of interaction only request of FTS trigger or trigger by itself

him/herself

Remark:

Today the term “drone” connotes a vehicle, that has limited flexibility for accomplishing

sophisticated flights and flies in a (dull) monotonous and indifferent manner. This type is not

able to take part in the air traffic of unreserved airspace. Drones are limited to reserved

airspace (SUA, TRA, Restriction areas etc.)

In special cases, complex measures may be taken (from long term co-ordination, PPR, TRA

establishment, NOTAM issue up to the use of a manned chase-aircraft) to assure ATC/ATM.

(Safety reasons and certification for unreserved/unrestricted airspace are not addressed here

and may limit “drones” generally to highly restricted airspace.)



Date: 10.12.01page 149

17.2 Autonomy State 1, - No autonomy

4-dimensional flight path fully pre-planned, pre-programmed

Operator

• presence continuous guidance and control

• possibility of interaction all interactions are “carefree handling” or via

a “FMS” on ground. Changing of

programming as well as direct flight path

control is possible

• necessity to interact operator must interact in all cases, when the

pre-programmed flight path and the whole

flight cannot be performed as planned

interaction depends from possible situational

awareness. In general, the operator acts as a

pilot of a manned aircraft as far as possible.

The limitations to do so are shown in previous

chapter.

AI-Pilot No

ATC

• presence/activity surveillance to the utmost degree as IFR-

traffic. This requires continuous contact to

operator

• possibility of interaction by advise to operator



Date: 10.12.01page 150

17.3 Autonomy State 2 – Autonomous manoeuvring, collision avoidance

4-dimensional flight path fully pre-planned, pre-programmed as in state

1

Operator

• presence continuous guidance and control

• possibility of interaction same possibility as state 1

• necessity to interact in principle the same necessity as state 1, but

some limited manoeuvring (e.g. ACAS II

collision avoidance, 3 dimension ADS-B

collision avoidance) is performed

autonomously by UAV and fed back

appropriate by to operator (and ATC).

Capability for autonomous manoeuvring

depends upon equipment with respect to

autonomous situational awareness,

autonomous decision making and air traffic

environment.

AI-Pilot No, but capability of autonomous

manoeuvring

ATC

• presence/activity surveillance and separation according

airspace structure,

continuous contact to operator

• possibility of interaction by advise to operator

Remark:

Limited automatic, autonomous manoeuvring is not connoted as AI-pilot, AI-pilot-function

contains aspects of routing, decision making etc. In case of autonomous manoeuvres are

occurring, the operator is informed by his instruments and / or warning devices and must

pass over the event to ATC.



Date: 10.12.01page 151

17.4 Autonomy State 3 – Autonomous, limited AI pilot available

4-dimensional flight path Mix of pre-planned (on ground) and

autonomous routing including terrain,

airspace structure, and purpose of flight

related aspects

Operator

• presence continuous supervision

• possibility of interaction as in other states

• necessity to interact due to the assistance by the AI-pilot, the

necessity to interact with UAV is reduced and

limited to special cases and emergencies

AI-Pilot limited AI-Pilot available

ATC


airspace structure.

Continuous contact to AI-Pilot and Ground-

Pilot

• possibility of interaction via CPDLC, in this case CAI-PDLC

via advice to Ground-Pilot

Remark 1:

In this case, ATC has contact to the Ground-pilot as well as contact to the AI-Pilot.

Both “pilots” can control the UAV, and both pilots have to give feed backs to ATC.

The AI-Pilot has to give feed back of his actions to ATC and Ground-Pilot.

This poses serious interface priority problems and data link problems.



Date: 10.12.01page 152

Nevertheless any appropriate intermediate state between state 2 and state 3 has the

potential to increase safety.

Remark 2:

ATC has to interact with the AI-Pilot twofold

• ATC has to give advise to AI-Pilot

• AI-Pilot has to request clearances from ATC and accept, acknowledge the received

clearance.

Interaction with the AI-pilot is problematic in cases of hurry, stress etc. with respect to

technical feasibility as well as to unambiguity and safety.

A partial solution may be found in the future data-link communication between ATC and

aircrews in an ADS-B environment. Considerable research effort must be spent in this area.



Date: 10.12.01page 153

17.5 Autonomy State 4 – Fully autonomous with sophisticated AI-Pilot

available

4 dimensional flight path Preplanning may be done by AI-Pilot as well

as autonomous routing including terrain,

airspace, structure and purpose of flight

related routing

Operator

• presence no continuous supervision necessary for

other reasons than safety back up

• possibility of interaction Foreseen as safety back up only, for other

reasons not necessary or transferred to ATC

• necessity to interact none, interaction by operator is automatically

defined as emergency

AI-Pilot Full AI-Pilot available

ATC


airspace structure

• possibility of interaction via AI-Pilot (as safety back up via operator)

Remark:

This state 4 is in the future but nevertheless envisaged already today. 2 main motivations

exist, to realise fully autonomous flight:

• complete military missions, using parts of the unreserved airspace

• Giving more autonomy to air transport business in the direction of a comprehensive

assistance to the pilot.

If ATC has to interact via operator, this fact is automatically defined as an emergency

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