2017 ACAS Xu Flight Test - Massachusetts Institute of ... ACAS Xu Flight Test •Introduction...

DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.

Edward Londner

5 December 2017

2017 ACAS Xu Flight Test

Sponsor: Neal Suchy, FAA AJM-233

Lincoln Laboratory Air Traffic Control Workshop 20172017 ACAS Xu Flight Test - 2EHL 5 December 2017

UAS Airspace Operations

Detect and Avoid is a key technology to achieve integrated UAS operations

Limitations on Flight– Governmental users rely on restricted

areas, significant operational burdens for airspace access

– Civilian use restricted to small UAS within line of sight

• See-and-Avoid requirement (14 CFR 91.113)

– UAS unable to perform this function

– Use of chase aircraft and advanced coordination with ATC for temporary flight restrictions

File and Fly

– Same process as manned aircraft

– No advanced coordination required

• UAS perform Detect and Avoid– Seamlessly integrate with traffic in all

airspace classes

– Conduct operations at any altitude

– No constraints on visual conditions

TodayToday Desired FutureDesired Future


Detect and Avoid Overview

Primary Detect and Avoid system functions:• Remain Well Clear: strategic maneuvers to maintain separation• Collision Avoidance: tactical, last-minute maneuvers to avoid a collision

Detect and Avoid (DAA) is the capability of an unmanned aircraft toremain well clear from and avoid collisions with other airborne traffic

Collision Avoidance• Warning level• Automatic response• ~40 seconds from CPA

Remain Well Clear• Caution level• Coordinate response with ATC• ~75 seconds from CPA


Current Airborne Collision Avoidance System Traffic alert and Collision Avoidance System (TCAS)

Range Altitude Bearing

Transponder-only

TCAS

TCAS

Coordination

TCAS uses onboard surveillance and a pilot interface to provide independent collision avoidance protection

3104020

315

305

320

300

340

360

280

.818 STD

AP1

A/THR

FL 310

SPEED ALT L-NAV

7

2

Traffic Display Vertical Maneuver GuidanceCockpit Displays

Air-to-Air Surveillance

• Traffic Alert (TA)“Traffic, Traffic”

• Resolution Advisory (RA)Ex. “Descend, Descend”

• Termination of alert“Clear of Conflict”

Aural Annunciations


Next Generation SystemNext Generation System

Next Generation Airborne Collision Avoidance System (ACAS X)

• Lincoln Advanced Concept Committee project initiated in 2008

• FAA program since 2009‒ Improve safety‒ Reduce unnecessary alerts‒ Support new platforms, airspace

operations, surveillance sources‒ Streamline development process

• Lincoln leading:‒ Threat logic ‒ Surveillance and tracking ‒ Maneuver coordination‒ Flight test planning

ACAS X supports airborne detect and avoid requirements

DynamicUncertainty

StateUncertainty

Additional Surveillance

Sources

Improvedand Flexible Threat Logic

StandardInterface

0 0 0 0 0 1 0 1 0 1 0 1 1 0 0 0 0 0 0 1 1 1 0 1 0 1 1 0 1 1 1 1 1 0 0 0 1 1 0 0 1 1 1 0 1 1 0 0 0 1 1 0 1 1 0 0 1 1 1 1 0 0 1 1 1 0 1 1 1 0 1 1 0 1 1 0 1 0 1 0 0 1 0 0 0 0 1 1 0 0 1 0 1 1 1 1 0 1 1 1 1 1 0 1 1 0 0 1 0 1 1 1 1 0 0 1 1


User Group

Surveillance Technology Advisories

Logic Finalized; Final MOPS

Development

ACAS XA

Current TCAS II users

(large aircraft)

Active radar supplemented

with ADS-B

Same as current TCAS II

ACAS XO

Users of specific operations

(e.g. parallel approaches)

Active radar supplemented

with ADS-B

Procedure-specific alerts for designated

intruders, global alerts for others

Under Active Development ACAS XU

Unmanned aircraftPrimary radar,

active (secondary) radar, ADS-B

Vertical and horizontal advisories

Future ConceptACAS XR

Rotorcraft TBD TBD

ACAS X Variants

Focus of this briefing


2014 2015 2016 2017 2018 2019 2020 2023 2024

ACAS X Development Timeline

ACAS XA,XOStandards development FAA GuidanceOp Eval Operational Use

Initial MOPScomplete

FAA TSO & AC Complete

2015 Full SystemFlight Test

ACAS XU

Flight Test 2 Initial MOPScomplete

• Viability of look-up table approach• Suitability of ACAS X RAs• Interoperability with TCAS• Legacy TCAS surveillance

Xa, Xo: August 2013 Xu: Nov-Dec 2014

R & D

2013 Proof of Concept Flight Test

2014 Proof of Concept Flight Test

• Vertical and horizontal maneuvers• ADS-B, radar surveillance• Interoperability with TCAS• Autonomous maneuvers

Xa, Xo: August 2015

• Mature logic• ACAS Xo designation• Passive surveillance validation• Enabled operational evaluation

R & D FAA GuidanceStandards development LIP

Focus ofthis briefing



• Introduction

• Flight test overview

• Flight test execution

• Preliminary results

• Summary


Key Objectives:• Confirm expectations set

by modeling and simulation

• Demonstrate new features of ACAS Xu system

• Collect data in support of evaluation and follow-on development

• Integrate ACAS Xu logic onto prototype avionics and test aircraft

ACAS Xu 2017 Flight Test Objectives

• 245 scripted encounters between 2 or 3 aircraft• Edwards Air Force Base, California• June 13 – August 1, 2017

Successfully flight tested baseline ACAS Xu Detect and Avoid logic


Detect and Avoid Flight Test featured several firsts:1. Correlation of three surveillance sources: ADS-B, active surveillance, and primary radar

2. Optimized selection of horizontal or vertical advisories

3. Blended vertical and horizontal advisories against multiple intruders

4. ACAS Xu equipped on manned aircraft acting as surrogate UAV

5. Interoperability between ACAS Xu and Xa

6. Caution and Warning Level DAA guidance

Flight Test Statistics

Total Fly Days 12

Logged Test Flight Time 100+ aircraft-hours

Test Cards • Planned: 241• Total Flown: 245


Successful flight demonstration was a critical milestonethat will enable implementation of full DAA baseline

DAA = Detect and Avoid


Organizations and Roles

AFRC = Armstrong Flight Research Center

• Prototype ACAS Xu• Operator of test aircraft N3GC

• ACAS Xu integration, V&V• Analysis of results

TCAS Program Office• ACAS X sponsor• Manage development, cost,

schedule, risk

• Flight test hazard identification• Safety support

• Prototype ACAS Xu• Operator of test aircraft N6754H

• Ikhana integrationand hardware support

AFRC*• Responsible test organization• Operator of test UAS Ikhana• Develop flight test objectives,

success criteria, schedule, analysis plan

• Develop threat and surveillance logic

• Develop and test encounter scenarios

• Develop test card automation software

• Coordinate participating organizations

• Coordinate data collection, disseminate collected data

• Coordinate and conduct flight test analysis

• Document results

• Develop flight test objectives, success criteria, schedule, analysis plan

• Develop threat and surveillance logic

• Develop and test encounter scenarios

• Develop test card automation software

• Coordinate participating organizations

• Coordinate data collection, disseminate collected data

• Coordinate and conduct flight test analysis

• Document results

Lincoln LaboratoryLead Organization

• Risk tracking• Documentation


Surveillance and Tracking Module (STM)

• Correlation Tracker– Developed by FAA– Best Source Selection

• Fusion Tracker– Developed by Honeywell

Interrogation, Reply1030/1090 MHz

1090ES ADS-B

Primary Air-to-Air Radar*

SurveillanceSources

– Guidance bands– Caution and warning

level guidance

Turn Left, heading 340

ACAS Xu architecture is adaptable to diverse UAS platforms and performance

* Radar designed by General Atomics

ACAS Xu Architecture

Threat Resolution Module (TRM)

• Detect and Avoid Alerting– Caution and warning

advisories– Suggestive guidance

bands– Intelligent selection of

horizontal or vertical advisories



• Introduction




• Summary


ACAS Xu Flight Test Overview

1090ES ADS-B

TCAS, ACAS Xa, ACAS Xu

• 245 scripted encounters• 12 encounter categories• Edwards Air Force Base,

June 13 – August 1, 2017• Emphasis on system

configuration changes

14

Critical Facts

• Surveillance inputs• Prototype manufacturer• Ownship performance• Coordination rank• Response to advisories

System Configurations

TCAS II, ACAS Xa, ACAS Xu, Mode C

• 1090ES ADS-B

• 1030/1090 Active Surveillance

• Primary Air-to-Air Radar(General Atomics)

Surveillance SourcesPrimary target


Flight Test Aircraft

N6754H

N6754HOperator: L3-ACSSC90 King AirACAS Xa, Xu, Mode C

IkhanaOperator: NASA ArmstrongMQ-9 Predator BACAS Xu (Primary Ownship)

N3GCOperator: HoneywellC90 King AirTCAS II, ACAS Xa

N3GC

Ikhana


• Typically two minutes long

• Pre-flight M&S to develop and validate cards

Priorities Category #

DemonstrateACAS Xu Features

Deliberate Alerts 85

Deliberate Alerts with Turns 21

Remain Well Clear 24

Level-off Blunders 19

Multi-threat Encounters 10

Operational Relevance

500’ VFR/IFR 14

1000’ IFR/IFR 14

Descending Overtakes 18

Collect Data

Holding Patterns 3

General Atomics 4

Surveillance 20

Multi-threat Surveillance 13

Total 245

Scripted Encounters


Test Card DA-72


Flight Test Corridor

Edwards AFB

Restricted Area

• Restricted airspace near Edwards Air Force Base (AFB)

• Ikhana limited to shaded region during testing

• Temporary partial airspace losses frequent due to other research activities

• Contingencies in place to reduce impact of airspace losses



• Test area (red) a subset of restricted area R-2515

• Manned intruders permitted to operate outside of restricted area

• Typical test aircraft speed: 180 knots (3 nmi / minute)

12 n

mi

35 nmi



• Test area (red) a subset of restricted area R-2515

• Manned intruders permitted to operate outside of restricted area

• Typical test aircraft speed: 180 knots (3 nmi / minute)

150 waypoints used during flight test

12 n

mi

35 nmi



N6754H N3GCIkhana

“Worms” are 90 seconds long


Data Collection

• All data successfully collected

• Critical data sources included ACAS Xu TRM and STM recordings, truth data

• TRM and STM recordings– Analysis of threat and surveillance logics

– Simulation of flown encounters using recorded surveillance data

– Encounter playback with alternate logics

• Truth data– Differential or WAAS GPS

– Validation of surveillance models

– Surveillance quality analysis

– Encounter plotting

TRM = Threat Resolution ModuleSTM = Surveillance and Tracking Module



• Introduction




• Summary


Achievements

• Achieved test objectives

• Collected all data

• ACAS Xu performed as expected

• Demonstrated new system features

• Demonstrated multiple vendor implementations of system logic

• Demonstrated system performance against multiple intruder types

• Demonstrated coordination between ACAS Xu and TCAS II


Dual Horizontal ResponseTest Card DA-72

IkhanaN6754H

TurnRight

Clear ofConflict

TurnRight

Clear ofConflict Turn

RightTurnRight

Distance East (nmi)-6 -4 -2 0 2 4 6 8

Dis

tanc

e N

orth

(nm

i)

-1.5

-1.0

-0.5

-0

0.5

1.0

1.5

2.0

2.5IkhanaN6754H


Issues Requiring Analysis

Surveillance and Tracking Module

• Surveillance source switching

• Active surveillance tracker lag– Causing horizontal reversals during response scenarios

• False targets, tracks from General Atomics radar

• Comparison of correlation and fusion trackers

Threat Resolution Module

• Undesired horizontal reversals

• Ambiguity in suggestive bands

• Advisories issued against false radar targets

• Path crossing horizontal advisories

• Differences in ACAS Xu behavior between Ikhana and N6754H


Surveillance Source SwitchingTest Card DA-26

Intruder True Position (no alert)

Intruder Position Uncertainty (95%)

Switch from ADS-B to active

surveillance

LC L

L

C Climb Advisory (warning)

Turn Left Advisory (caution)


Next Steps

• Ongoing analysis of flight test results– Validation of modeling and simulation

– Investigation of observed issues

• Full DAA baseline implementation (early 2018)– Next version of system logic

– Resolution of undesired behaviors observed during 2017 Flight Test

• Flight test with Lincoln Laboratory Small UAS Test Bed (Summer 2018)– Parameter scaling to emulate large UAS flight testing

– Relaxed aircraft separation constraints

• Limited Implementation Program (2022)– Operational evaluation of ACAS Xu with Navy Triton aircraft

– UAS equipped with Xu in unrestricted airspace


Summary

• Lincoln Laboratory is leading development of Detect and Avoid (DAA) system ACAS Xu– Enable unrestricted UAS flight in national airspace– Logic adaptable to diverse UAS platforms

• ACAS Xu 2017 Flight Test demonstrated mature DAA logic, including intelligent selection of advisories based on ownship performance, surveillance, and encounter geometry

• Data from flight test enables validation of models, analysis of observed behavior, real encounters for ongoing system development

• Success of 2017 Flight Test enables full DAA baseline implementation in early 2018

DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.This work is sponsored by the Federal Aviation Administration under Air Force Contract #FA8721-05-C-0002. Opinions, interpretations, recommendations and conclusions are those of the author and are not necessarily endorsed by the United States Government.

Thank you! Questions?Email address: [email protected]


Acknowledgements

Group 42Brandon AbelJeremy AmundsonRod ColeEmilie CowenMatt EdwardsIan JessenJames KeefeErik KirsheyJ.P. LaPlanteD. Evan MakiRobert MossWes OlsonMichael OwenAdam PankenGregg ShoultsEmily SimonsJerry StankiewiczTom TellerRandy Wiken

Partnering Institutions• ACSS• Aurora Innovations• General Atomics• Honeywell• Johns Hopkins University

Applied Physics Laboratory• MITRE Corporation• NASA Armstrong

Technical CommunicationsChet Beals

FAA TCAS Program OfficeSponsor: Neal Suchy


Legal Notices

Distribution Statement A: Approved for public release; distribution is unlimited.

This material is based upon work supported by the Federal Aviation Administration under Air Force Contract No. FA8721-05-C-0002 and/or FA8702-15-D-0001. Any opinions, findings, conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the Federal Aviation Administration.

© 2017 Massachusetts Institute of Technology.

Delivered to the US Government with Unlimited Rights, as defined in DFARS Part 252.227-7013 or 7014 (Feb 2014). Notwithstanding any copyright notice, U.S. Government rights in this work are defined by DFARS 252.227-7013 or DFARS 252.227-7014 as detailed above. Use of this work other than as specifically authorized by the U.S. Government may violate any copyrights that exist in this work.

2017 ACAS Xu Flight Test - Massachusetts Institute of ... ACAS Xu Flight Test •Introduction...

Documents

Transcript of 2017 ACAS Xu Flight Test - Massachusetts Institute of ... ACAS Xu Flight Test •Introduction...