1 2212021 Auto ACAS Automatic Air Collision Avoidance

1 2/21/2021 Auto ACAS Automatic Air Collision Avoidance System The brief one. Bengt-Göran Sundqvist Saab Aerosystems 2005 -02 -02 03 -10 -06 1 SAAB AEROSYSTEMS

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Historic perspective – Losses of 37 Viggen Auto ACAS Auto GCAS • Automatic Ground Collision. Air Avoidance • Automatic Collision. System Avoidance System • Cooperaton Between Sweden and USA 1997 – 1999 • Technology demonstration program • Flight tested in F 16. between Sweden (FMV) and USA (USAF), • Currently under 2000 implementation and flight test in Gripen. – 2004 Funded (50 -50) by USAF Air Force Research Laboratory and FMV (totally 12 MUSD) • 03 -10 -06 4 SAAB AEROSYSTEMS

Auto ACAS - Cooperation 2000 2001 Koncept 2002 2003 Developm. Implementation Flight test LOCKHEED MARTIN 03 -10 -06 5 SAAB AEROSYSTEMS

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) 03 -10 -06 6 SAAB AEROSYSTEMS

The concept Auto ACAS Intuitive to first identify a collision …. . 03 -10 -06 7 SAAB AEROSYSTEMS

The concept Auto ACAS does not predict future collision. … and compute coordinated It escape continuously optimizes coordinated maneuvers. Datalink escape maneuvers. The maneuver is executed when these claimed spaces intersect (in time and space). Datalink 03 -10 -06 8 SAAB AEROSYSTEMS

The concept Auto ACAS Cones intersect Control is returned to the pilot Escape maneuver: roll 120 deg/s, followed by 5 g Cone radius • ½ Wingspan • Position uncertainty • Pred. error of trajectory Activate the escape maneuver! The aircraft fly within the claimed space Roll to the selected escape angle andrepresented apply nz The uncertainties are by cones 03 -10 -06 9 SAAB AEROSYSTEMS

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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. 03 -10 -06 11 SAAB AEROSYSTEMS

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 03 -10 -06 12 SAAB AEROSYSTEMS

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. 03 -10 -06 13 SAAB AEROSYSTEMS

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. 03 -10 -06 14 SAAB AEROSYSTEMS