Cooperative Stochastic Control for Optical Beam Tracking

Maintaining optical alignment between stations of a free-space optical link requires a persistent beam tracking operation. This is achieved using a position-sensitive photodetector at each station which measures the azimuth and elevation of tracking error. A pointing assembly adjusts the heading of transceivers according to measurement of the tracking error. The measurement at each receiver also depends on the pointing error of the opposite transmitter, therefore a cooperative beam tracking system can be regarded as two dynamically coupled subsystems. We developed a stochastic model for a cooperative beam tracking system to get insight into solution of an associated optimal control problem with goal of maximizing the flow of optical power between the stations.