A novel tracking means for distant ballistic missile targets

Abstract From the Canadian patent

A laser tracking system steers a beam of laser energy which is dithered in two directions to scan the surface of a moving object. A laser energy detector detects laser energy reflected from the target. Reflected energy is filtered to distinguish dither frequencies for signals in both directions, which signals are independently analyzed to determine the location of the target in relation to the laser beam. A bias signal is generated which causes the beam of laser energy to be steered toward a surface radius to be steered toward a surface with the largest compound curvature within the trackers' field-of-regard, to the target to the, tracked location on-target, or modified signals steer a …