| Intersatellite optical communication, in which the laser works as the signal-carrier, is a communication method of information transmission among satellites in the free space. It is recognized as one of the best approaches in spacecraft and satellite communications, and is also a research focus in international space research. A reliable optical communication is based on the high requirements of accuracy of laser pointing, however, the working environment of the satellite optical communications is complicated and the beam spreads too far. Therefore, in the practice, the Acquisition,Pointing and Tracking (APT) technology has been a technical difficulty in satellite optical communications.This thesis analyzes a typical international Intersatellite-communication, and puts forward a set of APT solutions which serve as optical links between MEOOL (Medium Earth Orbit) and ARTEMIS (Geosynchronous Earth Orbit) in the practice.Firstly this thesis introduces the concepts, functions, compositions and key technologies of APT. Then, more researches are made on the main structure of the terminal SILEX which is carried by ARTEMIS and performance requirements of APT on MEOOL in establishing MEOOL-ARTEMIS optical links. Moreover, this thesis outlines the whole structure of APT system and flow chart of controlling signals, describes four main parts(Acquisition Sensor,Tracking Sensor,Coarse Pointing Mechanism,Fine Pointing Mechanism)in ATP functions and their structure characters. [0]Furthermore, this dissertation concentrates on the entire process of establishing optical links between MEOOL and ARTEMIS, and analyzes the capture probability of establishing the optical links between two satellites. In addition, author stimulates scanning paths of APT system, and discusses the r and difficulties in Lissajous scan. Finally, According to the above analysis and design above, this thesis proposes the realization of the four parts, instruments applications, and related circuit design. |
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