General Atomics is flight testing a pre-production Due Regard radar, declaring it the first fully functional air-to-air radar for an unmanned aircraft that meets “due regard” requirements for operating in international airspace. The company started developing the electronically scanned radar in 2011 and plans to make it available for customer evaluation this year.

Testers conducted multiple flight tests of the radar on a Predator B unmanned aircraft in December at the General Atomics Gray Butte flight operations facility and nearby Edwards Air Force Base in Palmdale, Calif. They flew the Predator B in “scripted encounters” against multiple small- and medium-size manned aircraft. The testing verified the radar’s functionality on the unmanned aircraft and its integration with Tcas II, the traffic alert and collision avoidance system with resolution advisories for avoidance maneuvers, General Atomics said.

Due regard refers to an International Civil Aviation Organization requirement that military and state-owned aircraft be flown with “due regard for the safety of navigation of civil aircraft” over international waters. The General Atomics’ radar “will allow users to operate Predator B independently in international airspace without the need for land-based, sea-based or off-board airborne airspace surveillance,” said Frank Pace, the company’s president for aircraft systems.

The U.S. Navy has encountered problems in fitting a collision avoidance radar on its larger MQ-4C Triton, which could limit its operations in international airspace. In November, the service issued a request for information to industry seeking solutions for radar and antenna systems.

General Atomics is participating with NASA, the Federal Aviation Administration and supplier companies in testing a full sense-and-avoid system (SAA) with due regard radar and Tcas II capabilities on NASA’s Ikhana Predator B aircraft. The onging effort aims to develop an FAA-certified system that would enable routine flights of unmanned aircraft in the U.S. national airspace system.

The due regard radar system stands at technology readiness level (TRL) 7 and is ready for potential customers to use for operational test and evaluation, General Atomics said. The SAA system stands at TRL 6 and awaits incorporating the requirements standards organization RTCA is developing through Special Committee 228.