Reserch On Satellite Optical Communication Coarse Pointing Scan Strategy And Tracking Control

With the rapidly development of science and technology since the 21 st century, the requirement for information capacity and transmission growing fast. Real-time communication has become the pursuit of the goal. As a new communication technology, satellite laser communication has many advantages in communication area. Therefore, laser communication attracted much attention since the concept of is presented put forward and become a hot topic of research in many countries. Because of the characteristics of laser, we need to establish acquisition, pointing and tracking(APT, acquisition, pointing and tracking) system to set up communication. In this paper, the Harbin Institute of Technology bear a certain type of satellite laser communication system as the background to make in-depth research on the coarse pointing scan acquisition strategy and the corresponding experimental verification.Scan and capture process is the key step for APT system. This paper focus on the coarse pointing system, and analyze the working and control principle of permanent magnet synchronous motor(PMSM), firstly. Then introduce three kinds of coordinates to simplify complex model of PMSM. Meanwhile, consider the vibration of the platform which influence the performance of the APT system. It is necessary to analyze the source and influence of the vibration of the platform. The simulation results of the vibration of the real satellite platform is proposed. Secondly, three scan capture schemes and two capture method are analyzed. Simulation results To compare the parameters which represent the performance of different scan schemes, the simulation results are carried out. And theoretical support for the optimization of the scanning strategy is provided. Some common scanning strategy are listed, the advantages and disadvantages are analyzed, the way to realize scan capture process is introduced. Based on the simulation of spiral scan strategy, spiral sine scan strategy is proposed and the simulation results is carried out to demonstrate its performance.Finally, Backstepping control method is adopted to solve tracking problem in the scan process of coarse pointing system. The basic principle of Backstepping control and the design method of the controller are introduced and the corresponding controller is presented. The simulation results of s ine spiral scan mode show that the controller we design can track the sine spiral scan angle position and satisfy the requirements of engineering precision. Since the vibration of satellite platform can influence the performance of the ATP system, a modified adaptive controller based on Backstepping control is presented. Simulation results show that the controller we designed can deal with the adverse effect caused by the platform vibration and get good controlling effect.