The U.S. Defense Advanced Research Projects Agency (DARPA) gained confidence in its concept for new unmanned combat aircraft during testing that wrapped up last month, according to the agency official managing the effort.

DARPA also recently established a consortium for the development of a common operating system for the Joint Unmanned Combat Air Systems (J-UCAS) , said Michael Francis, DARPA director of the J-UCAS program.

The purpose of the J-UCAS program is to develop networked clusters of unmanned aircraft that can suppress enemy anti-aircraft systems, strike other targets with precision-guided munitions and conduct surveillance.

The effort includes separate aircraft developed by Boeing Integrated Defense Systems of St. Louis, Mo., and Northrop Grumman Integrated Systems of El Segundo, Calif. under contracts awarded about five years ago. Northrop Grumman’s X-47 is being designed to take off and land from a U.S. Navy aircraft carrier, while the Boeing X-45 is intended to meet U.S. Air Force requirements like increased stealth, Francis said.

The Pentagon has already used unmanned combat aircraft in Iraq and Afghanistan. Those systems are generally controlled by operators on the ground performing functions similar to those of a pilot in a manned aircraft, Francis said in a March 4 interview.

In contrast, the J-UCAS aircraft are being designed with a higher degree of autonomy, Francis said. This reduces the number of troops needed to operate the aircraft, and enables the aircraft to continue missions deep behind enemy lines even if communications links are interrupted, he said.

The J-UCAS aircraft are expected to include both satellite and terrestrial communications links, Francis said. Program officials are examining the types of satellite links to include, he said.

The aircraft will likely need high speed connections to pass collected detailed imagery, although the pipes may not need to be as wide as those for aircraft like the Global Hawk, which take higher resolution pictures, Francis said. Some functions like command and control might be satisfied with lower bandwidth connections like the Iridium commercial telecommunications constellation, he said.

The most recent flight testing on the program has taken place with the Boeing X-45A aircraft, Francis said. DARPA and Boeing conducted a series of ground and flight tests with the X-45A that began in October 2004 and ran through February at Edwards Air Force Base in California that demonstrated a variety of the functions that the system may be called upon to perform.

This included having the vehicle stop itself after it began to approach the runway in order to conduct an automated test to ensure its systems functioned properly before flight, according to a Feb. 28 DARPA news release. Another test involved two X-45A aircraft communicating with each other to ensure a safe distance as they parked themselves after a mission was aborted before take off.

Flight tests during that period included passing control of a single X-45A from an operator at Edwards after takeoff to a second operator in Seattle via a commercial satellite link, and then back to the controller at Edwards for landing, Francis said. Control of two X-45A aircraft in flight was passed between controllers in separate locations at Edwards through line-of-sight communications.

Another flight test included two X-45A aircraft flying together to demonstrate the systems’ ability to take out enemy anti-aircraft batteries. The vehicles communicated autonomously with each other to determine which had a better shot at computer generated targets. The vehicles weighed factors including their speed relative to that of the threat’s location, weapons load, and available fuel, according to the news release.

DARPA and Boeing are now beginning to conduct another round of testing with the X-45A that will include increased autonomy with the aircraft, according to the news release. Those flight demonstrations, which are scheduled to run through August, are expected to include less operator involvement in finding enemy targets and increased maneuvering to avoid anti-aircraft fire.

William Barksdale, a spokesman for Boeing Integrated Defense Systems, did not respond to a request for comment by press time.

Northrop Grumman plans to begin flight testing its J-UCAS vehicle in 2007, according to Rick Ludwig, director of business development for the X-47 program.

The company expects to finish work this fall on a dedicated X-47 test facility that will enable the company to demonstrate key functions of the aircraft on the ground, Ludwig said. That facility is already partially operational, he said.

The company will use a modified F-18 aircraft to flight test some of the X-47 software beginning in 2006, Ludwig said.

Meanwhile, on Feb.13 DARPA formed a consortium that includes Boeing, Northrop Grumman, and the Johns Hopkins University Applied Physics Laboratory of Laurel, Md .

This effort is intended to yield software and other services that enable the system to function, according to a Feb. 23 DARPA news release. This could ultimately enable the military to add new capabilities to its unmanned aircraft independent of the chosen airframe, similar to the way that consumers can upgrade a variety of different computers through the purchase of a single new common operating system, Francis said.