Abstract: An electromagnetic (e.g., laser) beam acquisition and tracking system that is particularly useful onboard high-speed aircraft (10) to acquire and track a target (12) supporting a retroreflector (13) is disclosed. The acquisition and tracking system includes two deflection systems--a mechanical deflection system (19) and an acousto-optic deflection system (17)--for controlling the direction of the electromagnetic beam (14). The two deflection systems are serial, i.e., first one system deflects the beam and then the other system deflects the beam. The deflection systems are controlled in different manners, depending upon the mode of operation of the acquisition and tracking system, which comprise a search mode, a spiral search mode and a tracking mode. In the search mode of operation the mechanical deflection system (19), which includes one or more servo-driven scanning mirrors (54 and 56), relatively slowly sweeps the electromagnetic beam in either a line scan (18) or an area scan (16) search pattern.

Abstract: A modulated light beam is projected from a transmitter aircraft toward a receiver aircraft and reflected back toward the receiver aircraft by a retroreflector mounted on the receiver aircraft. The reflected light beam is received by the transmitter aircraft and is focused onto the face of an image dissector tube. The location of the reflected light beam on the face of the tube defines the position of the receiver aircraft in azimuth and elevation with respect to the position of the transmitter aircraft. The range difference between the two aircraft is determined by phase comparing the transmitted light beam with the received light beam. When used for in-flight refueling, further retroreflectors are mounted on a refueling boom and a similar technique is used to determine the exact location of the boom and its associated refueling nozzle.