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Showing ELOS for the VUSIL concept toShowing ELOS for the VUSIL concept to integrate UAS in uncontrolled airspace

Presentation at 3rd EU UAS Workshop, 19 October 2011

Andreas Udovic, Hans de Jong and Jürgen Vielhauer (DFS)

3rd EU UAS Workshop – Showing ELOS for VUSIL integration conceptPresentation_DFS_3rd_EU_UAS_Workshop_20111019_V01.pptx of 20

Contents

Participants in VUSIL II VUSIL concept Traffic display and Sense and Avoid display

In ol ed aircraft Involved aircraft

Example of a flight track and of conflict analysisExample of a flight track and of conflict analysis Results of analysis of all conflicts

Approach to safety analysis Assumptions and example of conservative approach Results for manned aircraft from literature Results for manned aircraft from literature Results for unmanned aircraft from VUSIL flight trials Comparison and conclusions


p

Participants in VUSIL II

Contracting body: German Federal Police (Bundespolizei)

Project partners Project partners: DFS Deutsche Flugsicherung GmbH (DFS) Federal Office of Defence Technology and Procurement (BWB)Federal Office of Defence Technology and Procurement (BWB) ESG (System and Software company; developed Sense and Avoid

Functionality (SAAFu)) EMT (manufacturer of fixed wing UAS “Luna”) SWISS UAV (manufacturer of unmanned helicopter “Neo”)

German Aerospace Centre (DLR): German Aerospace Centre (DLR):• Institute of Flight Guidance (Braunschweig)• Institute of Flight Psychology (Hamburg)


g y gy ( g)

VUSIL concept

UAS data link

Traffic display andSAAFu

Radar coverageby DFS

UASground station

Communication with ATC (FIS)

Mission profile


Communication with ATC (FIS)

VUSIL concept

Concept elements:

All traffic must be equipped with transponder (e.g. as in TMZ)

100% radar coverage (by DFS)

Separation minima: 0.5NM horizontal and/or 500ft vertical

If possible, collision avoidance based on existing VFR rules

Traffic display in control station Traffic display in control station

Sense and Avoid assistance system


y

Traffic display and Sense and Avoid display

Sense and Avoid display,developed by ESG

Traffic display,based on DFS Phoenix


Involved aircraft

Eurocopter 135 (Intruder)

Luna


Neo S-300

Example of a flight track

red: UAS Lunared: UAS Lunawhite: intruder


Example of conflict analysis

VUSIL flight tracks – Flight No. 07, Conflict 13

Conflict distanceVUSIL separations – Flight No. 07, Conflict 13

Flight tracks


Results of analysis of all Luna conflicts

No Flight Conflict No Real Extr Delta No Flight Conflict No Real Extr DeltaNo. Flight Conflict No. Real Extr. Delta

1 14 8 1.18 0.00 1.18 2 7 14 1.43 0.04 1.39 3 15 9 0 65 0 05 0 60

No. Flight Conflict No. Real Extr. Delta

12 11 2 0.71 0.25 0.46

13 6 7 0.37* 0.30 0.07

2 02 0 3 683 15 9 0.65 0.05 0.60 4 5 10 1.27 0.05 1.22 5 15 13 1.22 0.11 1.11

14 11 4 2.02 0.34 1.68

15 6 9 1.18 0.36 0.82

16 8 7 0.68 0.38 0.30

6 7 15 1.42 0.16 1.26 7 14 10 0.66 0.21 0.45 8 15 12 0.71 0.21 0.50

17 6 2 0.89 0.39 0.50

18 6 11 1.01 0.42 0.59

19 8 4 1.57 0.46 1.11

9 14 1 0.62 0.22 0.40 10 11 8 1.79 0.22 1.57 11 8 5 1.42 0.23 1.19

20 15 11 0.56 0.47 0.09

21 5 8 1.89 0.47 1.42

22 7 13 0.96 0.48 0.48

* Due to technical problem (frozen SAAFu), RPA pilot had wrong information about position of intruder


Results of analysis of all Neo conflicts

No Flight Conflict No Real Extr DeltaNo. Flight Conflict No. Real Extr. Delta23 9 4 0.47 0.31 0.1624 12 3 0.87 0.35 0.5225 9 3 0 50 0 37 0 1325 9 3 0.50 0.37 0.1326 15 2 0.56 0.43 0.1327 II.15 7 1.41 0.20 1.21


Approach to safety analysis

In order to concretise and investigate Equivalent Level of Safety,decompose Sense and Avoid and See and Avoid into sub processes: detection of traffic in the vicinity and

recognition and resol tion of conflicts recognition and resolution of conflicts,and estimate effectiveness of sub processes in terms of (conditional) probabilities, multiply and compare…probabilities, multiply and compare…

Effectiveness of “Sense and Avoid”

Effectiveness of conflict recognition×Effectiveness of traffic detection in %Effectiveness of conflict recognition and resolution in %

×

Effectiveness of traffic detection in %Effectiveness of conflict recognition and resolution in %

Eff ti f “S d A id”

×


Effectiveness of “See and Avoid”

Assumptions

1. Equipment (e.g. Sense and Avoid display) performs as may be expected from operationally used equipment. Trials affected by equipment failures that would be “rare” in operational context are disregardeddisregarded

2. Manned flights are conducted by single pilots, which is not2. Manned flights are conducted by single pilots, which is not unusual for VFR flights

3. For the rest the comparison between Sense and Avoid and See and Avoid has been made in a conservative manner:

pessimistic for Sense and Avoid pessimistic for Sense and Avoid optimistic for See and Avoid


Example of conservative approach

compared to

M d i ft R ti i ft Manned aircraft Reacting aircraft

Unmanned aircraft Non-reacting aircraft


Results for manned aircraft

Unalerted Air-to-Air Visual Acquisition, JW Andrews, Lincoln Laboratory, MIT, 1991: Flight tests with 24 “test” pilots in Beech 33 (not aware that they

ere obser ed regarding traffic detection)were observed regarding traffic detection)

During each flight three encounters planned with Cessna 421During each flight three encounters planned with Cessna 421

Encounters within 60° left – 60° right and 10° up – 10° down 500 ft vertical separation for safety

Safety pilot in Beech noting time at which test pilot detects Cessna Safety pilot in Beech noting time at which test pilot detects Cessna

Result: 36 of 64 encounters were timely detected by “test” pilot – 56%


y y p %


120° angle from aircraft 1120 angle from aircraft 1

120° angle from aircraft 1

v1

1 Collision point

Aircraft 1

v22

Aircraft 2



2 8

3

° ° °

v=v2/v1

2 2

2,4

2,6

2,8 1>60° 1=60° 1<60°

1,6

1,8

2

2,2

1

1,2

1,4

,

0,4

0,6

0,82<60°

2=60°

0

0,2

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180

2>60°



Optimistically assuming that

the conflict geometry is such that pilots of both aircraft could see each other in aforementioned angles andeach other in aforementioned angles and

the events that pilot of aircraft 1 sees aircraft 2 is independent from pilot of aircraft 2 sees aircraft 1,pilot of aircraft 2 sees aircraft 1,

the overall probability of timely detection is (1 - 0.56)2 0.8

It is optimistically assumed pilots always successfully recognise and resolve a conflict provided they have detected the conflict partnerresolve a conflict, provided they have detected the conflict partner

Effectiveness of See and Avoid is optimistically estimated at 80%


p y %

Results for unmanned aircraft from VUSIL trials

“Effectiveness of traffic detection” could not be derived from VUSIL flight trials, as UAS pilots were expecting many conflicts

In view of assumed operational grade equipment, traffic detection is estimated to be at least 99% effecti eestimated to be at least 99% effective all traffic is clearly visible on Radar and SAAFu display effectiveness could be further enhanced with audible signalseffectiveness could be further enhanced with audible signals

Conflict recognition and resolution can be derived from VUSIL trials 25 of 26 conflicts successfully recognised and resolved Maximum likelihood estimate: 96%

Conservative* estimate: 78% Conservative* estimate: 78%*: value of effectiveness for which the event that at most 1 of 26 conflicts is not recognised or

resolved is still credible (i.e. has probability 5%)


Comparison and conclusions

Process Manned Unmanned

Traffic detection 80% 99%

Conflict recognition and resolution

100% 96% (max likelihood)78% (conservative)( )

Overall 80% 95% (max likelihood)77% (conservative)

Under assumption of operational grade equipment,effectiveness of Sense and Avoid in the VUSIL concept is

similar to that of See and Avoid using a conservative approach similar to that of See and Avoid using a conservative approach better than that of See and Avoid using comparable estimators

The VUSIL concept provides and Equivalent Level of Safety for unmanned aircraft than for manned aircraft in a normal VFR context


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