1. Sense & Avoid for UAV Systems
ASAS TN 2 Meeting, Glasgow – September 12th 2006

2. 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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3. GROUND CONTROL STATION
WHAT IS A UAV SYSTEM ?
UAV AIR SEGMENT
AIR VEHICLE
PROPULSION
AVIONICS
MISSION PAYLOAD
DATA LINK
LAUNCH & RECOVERY /
TAKE OFF & LANDING
SYSTEM
GROUND CONTROL STATION
OPERATORS
UAV GROUND SEGMENT
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4. UAV Systems live in a complex world
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5. Ground Control Station
Payload operator
Mission controller
Thorough human factor studies has resulted in a dynamic and efficient working environment
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6. 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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7. 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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8. The Sense & Avoid Function
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.
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9. 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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10. 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 :
Co-operative traffic
Surrounding traffic carrying “Off the shelf” equipment enabling exchanges, like Transponders Mode S, or emerging technologies like ASAS/ADS-B
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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11. 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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12. 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 ft
Mode S #2 to TCAS #1
I am aircraft #2
I am at ft
Climb !
-08
Automatic Modes must be introduced
Safety Case to be developed
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13. Non co-operative technologies
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) ?
Flight Tests / Simulations must be performed
Safety Case to be developed
Non co-operative technologies should complement co-operative
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14. 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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15. 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
Automatic
Alert to Ground Operator
Managed by Ground Operator & ATC
STRATEGIC AWARENESS
Management of potential hazards:
Terrain
Traffic
Weather
TACTICAL AWARENESS
Alerts on threats
Terrain
Traffic
Weather
REACTIVE
MODES
Safety Net
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16. 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.
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