cd analysis - atm seminar...2013/05/24 · title cd analysis author tgaydos created date 5/24/2013...

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Analysis of Conflict Detection For

Performance Trajectory-Based Descent

Operations

Travis L Gaydos

Elida C Smith

Bill Liao

Liya Wang





Overall Question

• Trajectory-based descent operations

introduce changes to the current

environment, how do those changes affect

currently implemented conflict detection

automation?

– Studied for 3D PAM operations

2





3D PAM Research Partners

3





Meter

Fix Triangular Delay Paths Generated in ARTCC

Airspace:

Waypoint Insertion Using

Place-Bearing-Distance (PBD)

Path Stretch

Start

Path Stretch

End

TOD

3D PAM Target Domain

TMA Freeze Horizon

Source: 3D Path Arrival Management Concept of Use, Version 2.1

What is 3D PAM?

• Objective: Increase delivery accuracy over metering fix while enabling more efficient and environmentally friendly aircraft vertical profiles

• High level description: Concept relies on ground and airborne automation to compute and execute advisories for conflict-free trajectories from cruise altitude to a time-based metering fix

4





Environment Changes

Closed Loop Maneuvers During Metering

Path Stretch turn out waypoint

Path Stretch return waypoint

Path Stretch turn back waypoint

SNY 120 065

YANKI

Place Bearing Distance

SNY

5





Environment Changes

Speed Profile Agreed Upon

6





Environment Changes

More Near-Idle Thrust Descents

TODAY NEAR-IDLE

7





NWA571

320P

956D438

M75

EDA

NWA561

320P

948D472

M72

EDA ◊

◊

Conflict Detection Requirement Change

Arrival to Arrival Must Be Probed

8

It may not be intuitive

that these aircraft could

be conflict if the

controller is not aware of

the large path stretch

previously assigned to

NWA561

8





9

Now add many

more aircraft

flying varying

path stretch

maneuvers

Conflict Detection Requirement Change

Arrival to Arrival Must Be Probed





Important Current Conflict Detection

Automation Limitations

• Conflict detection does not utilize agreed upon

descent speed for modeling

– Not in current flight plan

– Modeler not designed to utilize

• Conflict detection does not utilize fact that

aircraft flying near-idle

– Performance data based on today’s operations

where few idle-thrust descents occur

10





Study Design

11





Study Design

12





Metric Definitions

= Notification = True Conflict

= True Alert

= False Alert

= Late Alert

= 3 minutes

= Missed Alert

= Missed Alert

Start Time End

13





False every ~ 2.5 to 3 minutes on average

False Missed/Late True

Baseline 35 0 7

1. Measure in terms of pair of aircraft with at least 1 arrival

2. Measure only after all 3D PAM advisories have been provided to the pair

14





Possible Improvements for Trajectory

and Conflict Prediction

1) Parameter Changes

2) Aircraft Performance Data Changes

3) Trajectory Modeling Changes

(utilize increased info)

Implementation

Simplicity

15





Possible Improvements for

Conflict Prediction

1) Parameter Changes

- Based on past research to find

optimal values in today’s

environment

2) Aircraft Performance Data Changes

3) Trajectory Modeling Changes

(utilize increased info)

Implementation

Simplicity

16





Conformance Box

Vertical Unchanged

+/- 300 ft = level flight

+/- 1000 ft = climb/descend

+/-

2.5

nm

+/-

1.5

nm

+/- 1.5 nm

+/- 1.3 nm

17





Likelihood

Time to Predicted Conflict (minutes)

Pro

bab

ilit

y o

f C

on

flic

t

0

0.2

0.4

0.6

0.8

1.0

20 16 12 8 4 0

18





Tactical Check +

/- 2

.5 n

m

Prediction Look-ahead Larger

Prediction

Buffer

Conformance Box

19





False Missed/Late True

Baseline 35 0 7

Likelihood Changes 35 0 7

Conformance Box

Changes

33 0 7

Tactical check 35 0 7

Combination of all of

above

33 0 7

False every ~ 2.5 to 3 minutes on average

1. Measure in terms of pair of aircraft with at least 1 arrival

2. Measure only after all 3D PAM advisories have been provided to the pair

20





Reasons For Results

• Only slight reduction in False Alerts

• Arrival vs Over-flight = ~45% of false alerts

– Magnitude due to scenario design, but illustrates

this will most likely be problem

• False drops by ~85% if alerts after TOD are

removed

• Why?

– Trajectory Modeling Off – Particularly Descents

• TOD – descent gradient

• Longitudinal – descent speeds not correct as does

not utilized agreed upon speeds

21





Summary

• Important to understand TBO concepts

interaction with currently implemented

automation

• 3D PAM changes would cause issues for

currently conflict detection

– Descent portion of flight not modeled well for

near-idle thrust descents

– Performance data update or modeler changes

are needed

22





False Alert Case Study:

UAL1463 (Arr) vs COA261 (Ovr)

23





COA261 vs UAL1463

Current Distance

Between Aircraft

No Alert Yet

TOD Prediction

Is Early

X coordinate

Y c

oo

rdin

ate

Alt

itu

de

(fee

t)

Flight Duration Since

First Track Point (seconds)

Gro

un

d S

pee

d (

kts

)



Red = Actual

Blue = Predicted





COA261 vs UAL1463

Predicted Problem

Location

Predicted

Problem

Location

Noticed Muted

Red Alert

X coordinate

Y c

oo

rdin

ate

Alt

itu

de

(fee

t)



Gro

un

d S

pee

d (

kts

)







COA261 vs UAL1463 Notice Muted

Red Alert

Less Than 5nm Predicted Problem

Location

X coordinate

Y c

oo

rdin

ate

Alt

itu

de

(fee

t)



Gro

un

d S

pee

d (

kts

)



Can’t update until

observing no

descent





COA261 vs UAL1463 Alert is removed

Updated because

Observed no descent

Aircraft past being

Close to 5nm

X coordinate

Y c

oo

rdin

ate

Alt

itu

de

(fee

t)



Gro

un

d S

pee

d (

kts

)







Back Up

28





Adherence Logic

• Set of rules for building trajectory dependent on if

aircraft has been conforming to flight plan or not

29





Speed Weighting

Currently

Observed Advisory

Speed

New = More

Weight Here

30





Turn Parameter

31

cd analysis - atm seminar...2013/05/24 · title cd analysis author tgaydos created date 5/24/2013...

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