December 5, 2007 Recent flight tests by the U.S. Air Force Research Laboratory and Boeing have demonstrated that unmanned air vehicles (UAVs) are capable of autonomous rendezvous with a tanker aircraft for refueling. Given their limited in size and payload capacity compared to larger manned aircraft, the development promises to significantly increase the the flight-times and range of of UAVs.
The government-industry program known as Automated Aerial Refueling (AAR) is seeking to develop and demonstrate systems that will enable UAVs to safely approach and maneuver around tanker aircraft so they can successfully perform boom and receptacle refueling operations.
The recent tests were conducted using a Calspan Learjet specially equipped to fly autonomously as a UAV and a Boeing KC-135R tanker. The autonomously guided the Learjet was successfully maneuvered into seven air refueling positions behind the tanker - contact, pre-contact, left and right inboard observation, left and right outboard observation, and break away - with the. During the tests a pilot flew the Learjet to the vicinity of the tanker before the flight control computer (built by Boeing Phantom Works) took over, guiding the aircraft for more than 1 hour and 40 minutes and holding it in the critical contact position for 20 minutes.
"By adding an automated aerial refueling capability to UAVs, we can significantly increase their combat radius and mission times while reducing their forward staging needs and response times," said David Riley, Boeing Phantom Works program manager for the AAR program.
"These tests show that we are making great advancements in system integrity, continuity and availability through improved relative navigation algorithms, control laws and hardware," Riley said. "They also show we are making great strides toward transitioning AAR technology into production."
The next step is a Phase II program that will include autonomous multi-ship operations and delivery of fuel to the surrogate UAV.