Analysis of complex axis control loop in satellite laser communications

Satellite laser communication involves communications between GEO satellites and LEO satellites. The optical link can be built by the accurate pointing and tracking, which often employs the combination effect of coarse pointing assembly and fine pointing assembly. In order to achieve this goal with double rotated wedged-plate lenses and fast steering mirror that perform the scanning function of the coarse pointing assembly and the fine pointing assembly, mathematic model of transfer function of control loop is obtained by analyzing the total control loop for such complex axis. One can also get the optimized programs between coarse and fine pointing assembly.