Cobham plc is preparing to demo what the Company believes will be the first in-flight docking of two unmanned aerial vehicles (UAVs) as it continues development of its autonomous aerial refueling system. Two specially designed UAVs — one a tanker, one a receiver — are being readied for flight-tests in restricted airspace at Yuma Proving Ground, Arizona, within the next month. One of the six-foot wingspan UAVs is equipped with an extendable refueling boom with drogue, or basket, and the other with a retractable probe. The two vehicles have been flown separately to check their flying qualities. The week-long trial at Yuma is planned to demonstrate fully autonomous rendezvous and docking, but will not involve actual fuel transfer, says Cobham subsidiary Sargent Fletcher. The sequence will begin with the tanker and receiver UAV in parallel orbits. On command from the ground, the receiver will move into the same orbit and chase down the tanker using its transmitted GPS position for guidance. Once it has closed to within 30 feet of the tanker using GPS, a sensor on the receiver’s nose will pick up a ring of infrared beacons on the refueling drogue and generate commands for the autopilot to guide the probe into contact with the basket.