Real-Time Trajectory Predictor

Calibration through Extended

Projected Profile (EPP) Down-Link

Jesper Bronsvoort & Greg McDonald

Airservices Australia

Mike Paglione & Christina M. Young

FAA

Joachim Hochwarth

GE Aviation Systems LLC

FAA/EUROCONTROL ATM R&D Seminar

Lisbon, Portugal, June 2015

Jean Boucquey

EUROCONTROL

Eduardo Gallo

Boeing Research & Technology Europe

Overview

1. Trajectory Synchronisation

2. Data-Link Standards

3. Aircraft Intent Generation based on EPP

4. Test Scenario

5. Real-time Calibration based on EPP

6. Conclusion

Trajectory Synchronisation

• Flight Management System (FMS) and ground-based Decision

Support Tools all have own version of the trajectory to be flown.

• The objective of air-ground trajectory synchronisation is to produce

trajectories in these disparate systems, increasing the likelihood of

flying the planned conflict-free and business preferred trajectories1.

1 KLOOSTER, J., TORRES, S., CASTILLO-EFFEN, M., SUBBU, R., KANMER, L., CHAN, D., & TOMLINSON, T. (2010). TRAJECTORY SYNCHRONIZATION AND NEGOTIATION IN TRAJECTORY

BASED OPERATIONS. PROCEEDINGS OF THE 29TH DIGITAL AVIONICS SYSTEMS CONFERENCE, SALT LAKE CITY, UT.

Data-Link Standards

• Data-link to synchronise trajectory information essential to TBO

• Currently (limited) trajectory information can be obtained by ATC from FMS via FANS-1/A as ADS-C Intermediate Projected Intent (IPI)

• Recently the Extended Predicted Profile (EPP) trajectory down-link standard was created by RTCA and EUROCAE to support air-ground trajectory synchronisation (DO-350/ED-228). EPP extends and improves IPI.

1990 2000 1980 2010 2020

Future Air Navigation

Systems 1/A

Aircraft

Communications

Addressing and

Reporting System

(ACARS) Aeronautical

Telecommunications

Network (ATN)

Link 2000+ ADS-C EPP

CPDLC & RNAV & ADS-C (IPI)

CPDLC

IPI-EPP Comparison Item Intermediate Projected Intent (IPI) Extended Predicted Profile (EPP)

General Maximum number of trajectory

change points (TCPs)

10 128

Maximum look ahead time 0-255 mins 15-1200 mins

TCP

Estimated

State

TCP location Yes (sequence of bearing and

distance from start point)

Yes (Latitude and longitude)

TCP altitude Yes Yes

TCP time Yes Yes

TCP speed No Yes

TCP

Specification

TCP waypoint name (if appl.) No Yes

TCP type specification No Yes

Level change, e.g. Top of Climb

(TOC) / Top of Descent (TOD)

Yes Yes

Lateral change Yes Yes

Speed change start Implementation dependent (at least

one of two provided)

Yes

Speed change end Yes

Crossover No Yes

Waypoint Depends if coincides with

lateral/vertical/speed change

Yes

Turn

Geometry

Fly-by turn radius No Yes

Fly-over turn radius/radii No No

Supports Radius to Fix (RF) legs No Yes

Add. Data Gross mass No Yes

Problem Solved?

• “The EPP unambiguously defined speed intent data (including speed

changes), and allowed for accurate reconstruction of the lateral path,

except for fly-over waypoints as the current EPP standard does not

include turn radii for these manoeuvres.” 2

• Problem of trajectory synchronisation solved?

2 BRONSVOORT, J., MCDONALD, G., HOCHWARTH, J, & GALLO, E. (2014). AIR TO GROUND TRAJECTORY SYNCHRONISATION THROUGH EXTENDED PREDICTED PROFILE (EPP): A PILOT

STUDY. PROCEEDINGS OF THE 14TH AIAA AVIATION TECHNOLOGY, INTEGRATION, AND OPERATIONS CONFERENCE, ATLANTA, USA

Test Scenario 1

• Brisbane (YBBN) to

Melbourne (YMML)

• RNAV SID RWY01

• Published Route

• RNAV STAR with RNP

transition to RWY34

• B737-500

• Cost Index 60

YBBN

YMML

Simulation Process

GE FMS

Simulator Flight Plan

EPP

Translator

EPP to

AIDL

Translator

Dali

Trajectory

Predictor

Ground

Trajectory

• GE FMS Simulator

• Boeing Aircraft Intent Description Language (AIDL)

• Airservices Dali Trajectory Modeller (BADA4)

SID

STAR

Reference

Trajectory

????

IPI to

AIDL

Translator

IPI

Results Scenario 1

2.2NM

Test Scenario 2

• Brisbane (YBBN) to

Melbourne (YMML)

• RNAV SID RWY01

• Published Route

• RNAV STAR with RNP

transition to RWY34

• B737-500

• Cost Index 60

• Derate take-off & climb

YBBN

YMML

Results Scenario 2

7.5NM

Test Scenario 3

• Brisbane (YBBN) to

Melbourne (YMML)

• RNAV SID RWY01

• Published Route

• RNAV STAR with RNP

transition to RWY34

• B737-500

• Cost Index 60

• Derate Take-off & Climb

• 5% Drag Factor

YBBN

YMML

Results Scenario 3

15NM

2500ft

Problem

• EPP provides the ability to synchronise lateral, speed and altitude

intent.

• But no

• ‘thrust intent’ as climb rating, anti-ice and high-idle.

• unknown aircraft performance characteristics such as drag factor.

• Lots of variables!

• Inclusion of all into EPP impractical

• bandwidth requirements.

• Confidential or proprietary information.

Calibration

• Torres et al (2011)3

• EPP was used to derive average vertical rate between EPP

points to update ground performance tables

• Kinematic approach

• Only works for single down-linked instance of EPP –

synchronises trajectory

• What if we could use EPP to synchronise the trajectory prediction

process rather than a single trajectory?

3 TORRES, S., KLOOSTER, J., HOCHWARTH, J., SUBBU, R., CASTILLO-EFFEN, M., & REN, L. (2011). TRAJECTORY SYNCHRONIZATION BETWEEN AIR AND GROUND TRAJECTORY

PREDICTORS. PROCEEDINGS OF THE 30TH DIGITAL AVIONICS SYSTEMS CONFERENCE, SEATTLE.

Calibration (2)

Initial

Conditions

Predicted

Trajectory

Aircraft

Intent

Aircraft

Performance

Model (APM)

Weather

Model (WM)

Trajectory Engine (TE)

Trajectory Predictor

• EPP allows for practically unambiguous description of aircraft intent

• Weather models can be accounted for by two-stage approach4

• Kinetic calibration of aircraft performance model

APMEPPTASTAS DTcgVm sin

4BRONSVOORT, J. (2014). CONTRIBUTIONS TO TRAJECTORY PREDICTION THEORY AND ITS APPLICATION TO ARRIVAL MANAGEMENT FOR AIR TRAFFIC CONTROL. SUBMITTED TO

DEPARTAMENTO DE SEÑALES, SISTEMAS Y RADIOCOMUNICACIONES. ESCUELA TÉCNICA SUPERIOR DE INGENIEROS DE TELECOMUNICACIÓN, UNIVERSIDAD POLITÉCNICA DE MADRID,

MADRID.

Calibration (3)

• Nominal mass from EPP

• Nominal A/C performance from BADA

• Optimization process to find c for

each EPP segment

EPP

APM

EPPTASTASm

DTcgV

sin

EPP1

EPP2

Dali Trajectory Predictor

Results – Nominal with Calibration 1.1NM

NOMINAL EPP TRAJECTORY

ALTITUDE BAND [FT]

C [-]

0 2127 1

2127 3466 1.00

3466 9292 0.97

9292 9661 1.03

9661 10000 1.04

10000 10355 1.00

10355 10896 1.01

10896 23013 0.99

23013 25452 0.98

25452 32000 0.99

Results – Derate with Calibration 1.0NM

EPP TRAJECTORY WITH DERATE

ALTITUDE BAND [FT]

C [-]

0 2113 1

2113 3044 0.72

3044 7480 0.72

7480 7958 0.78

7958 8991 0.82

8991 10000 0.83

10000 11156 0.84

11156 21768 0.96

21768 25452 0.97

25452 32000 0.99

Results – Derate & Drag Factor (Calb) 1.3NM

EPP TRAJECTORY WITH DERATE & DRAG FACTOR

ALTITUDE BAND [FT]

C [-]

0 2116 1

2116 3017 0.74

3017 7327 0.70

7327 7827 0.77

7827 8781 0.76

8781 10000 0.82

10000 11228 0.82

11228 21174 0.91

21174 25452 0.90

25452 32000 0.88

Application

Ground Trajectory based on

nominal EPP with derate

Application

Trial trajectory for 280KIAS

without calibration

Application

Trial trajectory for 280KIAS

with calibration

Confirmed by new EPP

down-link

Application

Confirmed by new EPP

down-link

Conclusion

• Not all variables that impact the air-ground trajectory synchronisation

process are included in the current EPP definition (DO-350/ED-228).

• It is impractical to include all these variables into a trajectory down-link

definition, therefore real-time calibration will be essential for effective

trajectory negotiation and management.

• With a single EPP down-link, the trajectory prediction process can be

synchronised through a calibration function, ensuring high accuracy

‘what-if’ trajectories and thereby anticipating the FMS behaviour upon

changes in aircraft intent.

EPP + Real-Time Calibration = Trajectory Synchronisation

Thank you

Flying has torn apart the relationship of space and time: it uses our old

clock but with new yardsticks.

— Charles A. Lindbergh.

Back-Up Slides

AIDL Generation Segment AIDL

Constant

Speed

HS(CAS/M) Speed targets provided EPP by trajectory change

points. TL(MCMB)

Acceleration EL(ESF) Acceleration segment fully defined by speed change

start and end point in the EPP. Energy share factor

be determined.

TL(MCMB)

Segment AIDL

Cruise HS(M) Altitude and speed provided by EPP trajectory

change points. TOC and TOD trajectory change

points identified. 128 points visible.

HA(PRE)

Segment AIDL

Pseudo-idle at

constant speed

HS(CAS/M)* Speed targets provided EPP by trajectory change

points. Altitude profile well established with all

relevant trajectory change points present in the EPP.

HPA(GEO)

Deceleration SL(CAS/M)* Deceleration segment defined by speed change start

and end point in the EPP. Speed law to model

deceleration can be determined from these EPP

points.

HPA(GEO)

• Climb

• Cruise

• Descent