Algorithms for Spatial Laser Beacon Acquisition

The pointing system for optical data transmission over unguided channels uses a return beacon from the receiver back to the transmitter to aid the reciprocal alignment of the two stations. We concentrate on CW or pulsed-beacon acquisition with array detectors in the presence of extended clutter in addition to background and receiver noises. Acquisition in the presence of a single interferer (jammer) is also considered. A maximum likelihood (ML) approach is used when preliminary scene information is available. In the case of unknown scenario, a picture-picture subtraction algorithm is considered for the pulsed laser. Performance is evaluated in terms of probability of an acquisition error for Poisson statistics of the photodetector output.