1. Bengt-Göran Sundqvist Saab Aerosystems 2005-02-02
Auto ACAS Automatic Air Collision Avoidance System The brief brief brief one.
Bengt-Göran Sundqvist
Saab Aerosystems
SAAB AEROSYSTEMS

2. SAAB AEROSYSTEMS

3. SAAB AEROSYSTEMS

4. Historic perspective – Losses of 37 Viggen
Auto GCAS
Automatic Ground Collision Avoidance System
Cooperaton Between Sweden and USA 1997 – 1999
Flight tested in F16.
Currently under implementation and flight test in Gripen.
Auto ACAS
Automatic Air Collision Avoidance System
Technology demonstration program between Sweden (FMV) and USA (USAF), 2000 – 2004
Funded (50-50) by USAF Air Force Research Laboratory and FMV (totally 12 MUSD)
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5. Auto ACAS - Cooperation
2000
2001
2002
2003
Koncept
Developm.
Implementation
Flight test
LOCKHEED MARTIN
LOCKHEED MARTIN
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6. Auto ACAS Objective/ Customer ”requirements”
Flight Test Demonstrate a system providing:
Protection through an automatic escape maneuver
No-nuisance operation, i.e. not interfere with normal operation (incl. Air Combat, Formation flight etc)
Fail-Safe operation
System designed as emergency last resort and aimed for both manned and unmanned A/C (UAV)
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7. The concept Auto ACAS Intuitive to first identify a collision …..
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8. The concept Auto ACAS … and compute coordinated escape maneuvers.
Auto ACAS does not predict future collision.
It continuously optimizes coordinated escape maneuvers. The maneuver is executed when these claimed spaces intersect (in time and space).
Datalink
… and compute coordinated escape maneuvers.
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9. The concept Auto ACAS The uncertainties are represented by cones
Control is returned to the pilot
Cones intersect
The uncertainties are represented by cones
Cone radius
½ Wingspan
Position uncertainty
Pred. error of trajectory
Escape maneuver: roll 120 deg/s, followed by 5g
Activate the escape maneuver!
Roll to the selected escape angle and apply nz
The aircraft fly within the claimed space
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10. SAAB AEROSYSTEMS

11. Summary Auto ACAS concept
Does not predict collision.
Continuously claims space, for the own escape maneuver, which is optimized against claimed spaces of other AC.
The size of the space depends on the physical size of the AC and a number of uncertainties. The size varies continuously as a function of these.
Automatically activates a safe escape maneuver when the optimized spaces intersect (in time and space).
The AC flies in the claimed space during the activation.
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12. Pros using the Auto ACAS concept
Safe as all uncertainties are accounted for in the size of the claimed space. All AC ensure that the own fly-out will stay within the own transmitted claimed space.
Nuisance free as the maneuver is deterministic for all AC it can be estimated with high fidelity and the uncertainties are thus kept small.
Handles dynamic situations (continuously optimized escape maneuvers for all AC).
Requires no handshaking (same optimization)
Easily adoptable to new platforms
Fail-safe
Robust against link drop-outs
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13. Cons using the Auto ACAS concept
ACAS will require transmission of data over the link, this can limit the transmission of tactical data.
Full operation is not safe in an out-of-network environment.
Complex - to fulfill requirements, given the limitations and uncertainties, requires heavy algoithms.
SAAB AEROSYSTEMS

14. Formation flight logic
When in Close formation: all activations are inhibited. all other aircraft yield to formation flying aircraft. When in Inhibit: the activation is inhibited against the specific aircraft. full ACAS functionality against other aircraft. The logic is by-passed during activation.
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