Global Hawk UAVs fly in close formation, move closer to autonomous aerial refueling

SAN DIEGO, 6 Oct. 2012. Northrop Grumman Corp. (NYSE:NOC), a global security company, the defense advanced research projects agency (DARPA), and NASA dryden flight research center have completed a series of flight demonstrations, moving DARPA's autonomous high-altitude refueling (AHR) program closer to demonstrating the first autonomous aerial refueling between two unmanned, high-altitude aircraft.

The flights, which featured two NASA Global Hawk unmanned aerial vehicles (UAV) – one configured as a tanker and the other as a receiver – were conducted at Edwards Air Force Base, Calif.

During the flights, which spanned Jan. 11 to May 30, the AHR team accomplished several goals. First, the two aircraft flew in close formation, thirty feet apart. During the close-formation flight, the aircraft rendezvoused and flew for more than 2.5 hours under autonomous formation control, with the majority of the time within 100 ft (or one wingspan) of each other.

The lead receiver aircraft extended and retracted its aerial refueling hose several times, completing all planned tests to validate the associated program hardware and software. The trail tanker aircraft also demonstrated precision control in formation with manual and automated "breakaway" maneuvers – important safety features and criteria of the test program.

Northrop Grumman and NASA Dryden Flight Research Center conducted several demonstration flights in the buildup to the close formation flight, which included tanker and receiver first flights and a distant formation flight Preparation for the flight included a calculated approach to ground and flight tests, which included extensive analysis, simulations, laboratory and ground tests as well as multiple safety review boards.

The $33 million DARPA AHR program aims to demonstrate autonomous fuel transfer between two Global Hawks, enabling flights of up to one week endurance. AHR is a follow-on to a 2006 DARPA autonomous aerial refueling demonstration (AARD), a joint effort with NASA Dryden that used an F/A-18 Hornet as a surrogate unmanned aircraft to autonomously refuel via a probe and drogue from a 707 tanker.

As part of the U.S. Navy's unmanned combat air system carrier demonstration program, Northrop Grumman is also developing AAR technology to help extend the operating range and flight duration of future carrier-based unmanned systems. The company plans to conduct AAR demonstrations in 2014 using the Navy's X-47B unmanned demonstrator aircraft.