基于大气信道内的空间激光通信演示验证实验，对系统光斑跟踪精度的影响因素进行了分析，研究了大气湍流对光斑跟踪精度的影响，建立了光斑质心检测模型，设计了一套信标光光斑粗精复合跟踪系统.搭建了室内测试实验系统，完成了大气湍流对光斑跟踪精度影响的测量，结果表明在中弱湍流时，跟踪精度随湍流增大有近似线性关系，系统整体跟踪精度在5~15 μrad之间，可较好地完成光斑跟踪功能.在野外环境开展的飞机-飞机激光通信演示实验中，对伺服系统的跟踪性能及跟踪精度进行实际测量，整体跟踪精度不大于15 μrad，与室内实验测试系统基本一致.

A set of beacon tracking servo system based on coarse-fine composite control was designed, which was aimed at demonstration test of space laser communication in atmospheric channel. Influence factors of tracking accuracy were analyzed and the impacts caused by atmospheric turbulence were researched in detail. A laboratory measurement system was constructed and the test about the effects of atmospheric turbulence on the optical spot tracking accuracy was completed. The results showed that the tracking accuracy was approximately linear with turbulent intensity increasing in weak-medium-strength atmospheric turbulence, which achieved spot tracking function well with a total system precision varied from 5 μrad to 15 μrad. An actual measurement for the tracking performance and accuracy of servo system was conducted in an air-air laser communication demonstration. The total tracking accuracy was no more than 15μrad and in accordance with the laboratory measurement system.