Acquisition and tracking of laser beams in space communications

A general consideration of the problem of acquisition and tracking of laser beams is given for intersatellite communications. An optimum multi-step system for antenna acquisition and pointing is determined. For the acquisition and pointing stage an equivalent bit rate is introduced. Using this criteria, an approach is derived to compare the acquisition system to the optimum one as well as to the communication channel with regard to the required optical power. The laser tracking system has been also considered. The advantage of a tracking system with two integrators has been shown.