General Atomics Aeronautical Systems has come a step closer to developing a viable sense and avoid (SAA) system for unmanned air vehicles (UAVs), a major requirement for UAVs to share the US national airspace with manned aircraft.

GA recently announced it has tested a proof-of-concept SAA system in partnership with the Federal Aviation Administration and Honeywell. It was the first successful test of the FAA’s airborne collision avoidance system for unmanned aircraft.

The company also has completed the first flight tests of a prototype air-to-air radar called due regard radar (DRR) that enables UAVs to detect and avoid other aircraft in flight and is the first of its kind designed specifically for a remotely piloted aircraft.

“Our latest sense and avoid test represents a major step forward for integrating RPA safely into domestic and international airspace,” Frank Pace, president of aircraft systems at GA-ASI, says in a statement. “Our proof-of-concept SAA system is now functional and ready for extensive flight testing with the FAA, NASA, and our industry partners.”

Eventually, GA plans to clear the due regard radar for routine operation in non-segregated civilian airspace over the US and abroad. Since 2011, the company has integrated automatic dependent surveillance-broadcast (ADS-B) – a system that augment’s radar tracking to provide pilots with advanced positioning data, though few general aviation aircraft yet carry ADS-B – aboard a Guardian UAV. It has also flight tested a prototype DRR aboard a Twin Otter aircraft.

The DRR also has been flight tested over Southern California aboard a Beechcraft King Air where it attempted to detect and track multiple test aircraft including general aviation aircraft beyond 10 miles. That test campaign opened the door for testing the system aboard a Predator B, the company says.

During flights on 4, 5 and 10 September at GA’s Gray Butte flight operations center in Palmdale California, a company owned Predator B was outfitted with the SAA system and demonstrated automatic collision avoidance, and sensor fusion that gave the remote pilot “a clear picture of the traffic around the aircraft”, the company says.

The Predator “proved the functionality” of the automatic collision avoidance system during maneouvres against aircraft outfitted with ADS-B. The FAA’s collision avoidance system also is design to work with existing traffic collision and avoidance systems (TCAS), which is currently the global standard system for commercial transport aircraft.

“Automatically executing collision avoidance maneuvers will enable Predator B to maintain safety in the National Airspace System in the unlikely event of a loss of the command and control data link,” GA says.

The company is working toward integrating the SAA system onto a Predator B owned by NASA, which will then serve as the primary aircraft for further testing through December at the Armstrong Flight Research Center in Edwards, California. The flight test campaign will evaluate the SAA system in a wide variety of both collision avoidance and self-separation encounters and will include a sensor fusion algorithm being developed by Honeywell, GA says.