Research On Optical Antenna And Coarse Tracking Technology Of Space Laser Communication

Space laser communication has been paid more attention by domestic and foreign countries because of its large data transmission, high efficiency, strong anti-interference and intercept ability and other characteristics, and been the research hotspot in the international. In recent years, many countries like America, Europe and Japan have obtained fruitful achievements in this field and China also has paid attention to the research of space laser communication and to make a certain progress.Laser communication is a comprehensive technology with many key technologies, especially applied in space commnication to be needed higher requirements. According to the demands of literature and actual projects, it researches two aspects including optical antenna and servo turntable of coarse tracking and also studies pointing error of antenna.A) It has analyzed types of optical antenna system comparatively aplied to laser communication so as to achieve high optical quality of optical antenna, and it has identified the research of optical antenna of space laser communication by cassegrain type and off-axis reflection type. According to the design parameters and the image analysis, it has put forward to improve the cassgrain structure and it has completed the design,optimization and analysis of two kinds of optical antennas with structure design of optical antenna including support of primary and secondary mirror and design of battery of lenses on the basis of two kinds of optical systems.B) It has researched some kinds of common servo turntable of coarse tracking in the optical antenna of space laser communication terminal and selected ten tracking of servo turntable of coarse tracking in the horizontal servo turntable of coarse tracking of latent type to be researched. According to the actual demands of projects, it has made the general structure design of turntable, selected important compinents and analyzed the whole machines, and then made the lightweight design of inside and outside of frames in the horizontal axis to strengthen the rigidity and to reduce the quality. It has also multi-objective optimization for outer lens cone of turnable axle in the latent type by continuous topological optimization technique; thus the stiffness and first natural frequency should be improved after r reinforcement plate.C) It has researched the terminal of horizontal type by sequential analysis on the basis of theory of errors. As starting with error source, it would obtain the transfering link of errors for terminal of latent type and then would make the analysis and simulation aiming to the error mathematics model by coordinate transformation, so the results of error mathematics model have showed that good accuracy pointing comes from coarse tracking mechanism with two structures.D) Cassette optical antenna and coarse tracking in the horizontal turntable have completed to process and adjustment and then do the test of optical antenna system and accuracy test of turntable of coarse tracking. The wave aberration of cassette optical antenna system with Ф252mm reaches 0.058λ(λ=632.8nm)and it has reached the wave aberration under the diffraction limit for imaging system, whose weight is only 19 kg, and its tracking precision of axis of coarse tracking system has reached 25.99μrad. The results have showed that cassette optical antenna and turntable of oarse tracking in the horizontal turntable could satisfy the demands for laser communication. According to the analysis and simulation, antenna of off-axis and servo turntable of periscopiec can also satisfy the space laser communication applications.According to the research on optical antenna and coarse tracking technology, this essay provide more freedom and the reference for practical projects in the laser communication system.