Power analysis of APT coarse tracking link of free space laser communication system

A typical structure of laser communication system was described briefly at first.Then the characteristics of coarse tracking assembly was analyzed.Link transmission including of beacon sending,free space transmitting and beacon receiving was described quantitatively.The characteristics of various system noise from CCD camera sub-system were analyzed.The characteristics of background light were also discussed.Then SNR of CCD output signal was calculated.System design was optimized,and important component was selected to make coarse tracking link meet the task requirement.