Sense and Avoid Avionics Evaluated in New FAA Test

Firebird 5 UAS. Photo: Northrop Grumman.

Firebird 5 UAS. Photo: Northrop Grumman.

The FAA and partners Northrop Grumman and ACSS, announced a series of successful flight tests of the sense-and-avoid avionics system for Unmanned Aerial Systems (UASs).

The flight tests led by Northrop Grumman were conducted at the Mojave Air and Space Port in Mojave, California. Participating were FAA staff from federally funded research and development centers, including the Massachusetts Institute of Technology Lincoln Laboratory and Johns Hopkins University Applied Physics Laboratory (APL), which developed the algorithms and software for ACAS Xu.

The FAA Traffic and Collision Avoidance System Program Office is developing the advanced Airborne Collision Avoidance System (ACAS) as a successor to the Traffic Alert and Collision Avoidance Warning System (TCAS) to support the objectives of its Next-Generation Air Transportation System Program (NextGen). All ACAS X variants detect conflicts with intruder aircraft, issue Resolution Advisories and coordinate maneuvers with other collision avoidance systems. ACAS Xa and Xo are intended for current TCAS users, and ACAS Xu is designed for UAS and other vehicles with new surveillance technologies and different performance characteristics.

“The flight tests collected data necessary to validate simulation models and help inform the continued development of ACAS Xu,” said Greg Boerwinkle, ACSS UAS Program Manager. “This is a critical capability to advance the economic viability and safety aspects of large UAS operations. The capabilities under development for large UASs to detect and avoid collisions will be substantially better than the ability of a pilot to see with the human eye and avoid collisions.”

Lincoln Laboratory and APL provided the ACAS Xu software to ACSS and supported the flight tests with overall system expertise. ACSS integrated and tested the ACAS Xu software and provided the hardware to host ACAS Xu leveraging its commercial T³CAS® product, which includes TCAS, transponder and Terrain Awareness Warning System (TAWS) functions. The T³CAS, with ACAS Xu Version 2 software, was integrated on the Northrop Grumman Firebird Demonstrator, an optionally piloted aircraft. Both ACSS and Northrop Grumman also provided manned aircraft that flew predetermined collision encounter geometries with the Firebird Demonstrator.

As part of the ACAS Xu development, the FAA is also working with the European Organization for Civil Aviation Equipment (EUROCAE) on international safety standards.

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