Research On Closed-Loop Beam Pointing Control Technology In Intersatellite Optical Communication

Comparing to microwave communications, intersatellite optical communications (IOC) have the advantages of larger information capacity, smaller antenna and higher security will be an important development direction of intersatellite communications. Recently, many countries have paid more attention to the development of IOC, such as USA, Europe, Japan and so on. Our country has also began to pay attention to it, and got some achievement already.In the intersatellite optical communication system, PAT is a key technique related to the establishment and maintenance of the communication link. Fine pointing mirror is a precise pointing device of PAT system, and its performance can directly influence the accuracy of pointing and tracking, so the method of controlling fine pointing mirror is very important.This paper has mainly investigated the following aspects of fine pointing mirror, which is the beam steering device of the intersatellite optical communication technology. Overview of the development of intersatellite optical communication is shown. Fine pointing steering devices which were used by our country and others, and their operating principle are analyzed. The experiment system including static performance test and dynamic performance test are shown in this paper. Fine amplifiers are used to do proportional and integral compute, the control method of fine pointing mirror driver is Closed-loop analog PID control, which avoiding the complexity and the slow frequency response of Closed-loop digital PID circuit.Static parameters which should be measured are pointed out and experiments are designed to measure the static performance,according to the accuracy requirement of the fine pointing system. Static performance is estimated, which is based on the analysis of the experiment data. Besides, experiments are also designed to measure the dynamic performance, and factors which influence the performance most are analyzed and dynamic performance is evaluated. These works reach the purpose of measuring the performance of the fine pointing mirror, meanwhile factors which influence the performance most and methods to improve the performance of the fine pointing mirror are found. This paper offer important basis of understanding the static performance and dynamic performance of fine pointing mirror driver and analyzing the factors which influence it. The fine pointing mirror driver controlling fine pointing mirror accurately are achieved, that provide instructive references to the applications of fine pointing mirror driver, establish the foundation of the research of the fine pointing system of the intersatellite optical communication.