Northrop Grumman is working on two separate challenges to wide-scale global operations of the Global Hawk/Triton unmanned air systems, Tom Vice, president of the company’s Aerospace Systems segment, said in Washington Aug. 20.

The more recent is the U.S. Navy’s issue of a stop-work order to ITT Exelis, which was developing the sense-and-avoid radar for the MQ-4C Triton maritime UAV. A sense-and-avoid capability, Vice says, is “vital” to the MQ-4C, which is designed to operate in oceanic airspace where there is no outside radar surveillance.

Vice said the radar problem is an “integration issue.” The ITT Exelis airborne sense-and-avoid (ABSAA) radar is a unique Ku-band, self-contained, active, electronically scanned array unit with three sub-arrays covering a 220-deg. field of view.

Vice says the company, the Navy and industry partners are exploring “a broad range of options” to allow the MQ-4C to operate safely and autonomously, including the timing of the sensor’s cut-in to production. “This is hard stuff,” he added. “The first UAS with no-kidding sense and avoid is hard stuff.”

Northrop Grumman is also trying to save the Euro Hawk program, which the German government canceled in May on the grounds that the estimated €600 million ($800 million) cost to certify the system for national-airspace operation would be prohibitive, and that even with that expenditure there was no guarantee that it could be approved.

“The challenge is airworthiness,” Vice said. “It’s not the system; it’s understanding how to operate it. The need is still there and the solution is the Euro Hawk. We don’t believe it’s time to give up.”

The Euro Hawk is a Global Hawk derivative equipped with an EADS Cassidian signals intelligence package.