Sense & Avoid for UAV Systems

ASAS TN 2 Meeting, Glasgow – September 12th 2006

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Agenda

What is a UAV System

The Sense & Avoid Function for UAV Systems Relationship with Air Traffic Control

Potential solutions

Conclusion

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WHAT IS A UAV SYSTEM ?

GROUND CONTROL STATION

UAV GROUND SEGMENT

LAUNCH & RECOVERY /

TAKE OFF & LANDING

SYSTEM

UAV AIR SEGMENT

OPERATORS

DATALINK

MISSION PAYLOADAVIONICSPROPULSION

AIR VEHICLE

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UAV Systems live in a complex world

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Ground Control Station

Payload operator Mission controller

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Applications

UAV Systems have a high probability to be developed for an increasing number of applications : Military systems : surveillance and target designation (ISTAR), countermeasures,

weapon delivery, etc... Security : border surveillance, maritime surveillance, anti-terrorism, sensitive sites

surveillance, etc... Civil applications : forest fire detection, pollution detection, agriculture, fishing, etc...

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UAV Systems specificities and constraints

“No Pilot on board” implies :

Situation awareness only based on data acquired by sensors, downloaded and analysed by to the ground operator (not equivalent to a pilot)

Latency exist due to the data transfer between the Air Vehicle and the ground station (up and down)

New failure configurations : Loss of Data Link : a sufficient level of autonomy is necessary Sensor Failure may be critical

No pilot able to “See and Avoid” , or “Detect and Avoid” neither in VMC nor in IFR

The « Sense And Avoid » function replaces the « detect and avoid »in all situations

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The global objective is to allow UAV Systems to operate safely within the non segregated civil and military airspace on a routinely basis.

For this purpose, the UAV must be able to identify and be identified by the surrounding traffic as well as by the ATC.

Sense & Avoid solutions must be agreed by Airworthiness and Operations authorities, and economically reasonable for Industry.

Sense and Avoid solutions are a must for UAV Systems, but may lead to benefits for manned aircraft safety.

The Sense & Avoid Function

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Regulation approach

Demonstrate an Equivalent Level of Safety between manned and unmanned aircraft

Make the difference between manned and unmanned aircraft transparent to ATC and to other users

However, UAV have specific characteristics to be known by ATC

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Basic needs for Sense & Avoid

Sense & Avoid should basically offer the capability - To provide traffic awareness to the pilot / operator- To perform avoidance manoeuvre in case of high collision risk

Traffic awareness :

1. Co-operative traffic Surrounding traffic carrying “Off the shelf” equipment enabling

exchanges, like Transponders Mode S, or emerging technologies like ASAS/ADS-B

2. Non co-operative traffic Air vehicles not fitted with such equipment : general aviation, gliders, balloons,

parachutes, ... Then the solution should need new sensors to replace visual acquisition

Avoidance manoeuvre :

Safety net to be performed timely, based on traffic information and if possible shared decisions

Typical current answer is the TCAS

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Additional needs

A global situation awareness system should also include :

Terrain awareness

TAWS are mandatory on most of the aircraft Terrain collision avoidance is also a need, in UAV Systems, for safety

of on ground population

Weather awareness The on-ground pilot must also be aware of weather threats

(precipitations, windshears, …) in order to avoid hazardous situations

Global situation awareness should be equivalent for manned and unmanned aircraft

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Existing co-operative technology : TCAS II

TCAS #1 to Mode S #2 Who are you? What is your altitude?

Mode S #1 to TCAS #2 I am aircraft #1 I am at 27 000 ft

Mode S #2 to TCAS #1 I am aircraft #2 I am at 29 000 ft

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- Automatic Modes must be introduced- Safety Case to be developed

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Technologies available for Non Co-operative traffic :

Light, medium range radars All weather recognition of other traffic by UAV Transfer of traffic information to Ground Operator Retasking by Ground Operator Automatic retasking ?

EO/IR techniques Specific EO cameras: low cost solution Can be improved by IR Why not use EO/IR payload when available (en route) ?

Non co-operative technologies

- Flight Tests / Simulations must be performed- Safety Case to be developed- Non co-operative technologies should complement co-operative

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Emerging technologies

ASAS / ADS-B may be useful for UAV Systems : ADS-B OUT : transfer of information (location, speed, UAV

identification...) from UAV to other users and ATC ADS-B IN : Improved traffic situational awareness for UAV

operators If possible in the future : 4D trajectories exchange Potential delegation of specific spacing tasks to UAV Operators,

like: Sequencing and Merging

TIS-B (Traffic Information Services – Broadcast) ground station may broadcast aircraft information gathered by

various means

Civil aviation emerging technologies may provide anticipated and consolidated situation awareness to UAV operators

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Potential Sense & Avoid solutions

Technologies Technologies exist to provide a Sense & Avoid system for UAV A mix of co-operative and non co-operative techniques is likely to be

necessary ASAS / ADS-B techniques seem promising for Sense & Avoid

Final system Should provide a global situation awareness to UAV Operators in

any configuration of traffic

STRATEGIC AWARENESSManagement of potential hazards:

Terrain

Traffic

Weather

TACTICAL AWARENESSAlerts on threats

Terrain Traffic Weather

REACTIVEMODES

Managed by Ground Operator & ATCAlert to Ground OperatorAutomatic

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Conclusion

UAV Systems are newcomers in the Air Traffic

ADS-B / ASAS techniques may be a good answer to Sense & Avoid issues for UAV Systems, and need to be analysed as such

Consequently, UAV Systems may be potential actors within the ADS-B / ASAS world and may have to exchange information with other users and ATC

Developments made for UAV Systems (automatic modes, enhanced situation awareness, ...) might reciprocally be beneficial to other civil aviation applications.