Research On Influence Of Joint Turbulence In Performance Of PAT For Satellite-ground Laser Links

Because of the traditional communication method has many disadvantages such as a small capacity of communication, large volume, a big weight, high power consumption equipment, weak anti-interference ability and confidentiality and so on. And compared with the traditional communication, ground-satellite laser communications technology has overcome the above shortcomings, for the current space technology research and development to create the necessary conditions. Therefore, researching on the ground-satellite laser communications technology has favored by more and more countries of related researchers.When the optical beam propagating in the atmosphere, atmospheric onflows of the different scale produce the optical refraction and diffraction, which results in turbulent effects, such as angle-of–arrival fluctuation. The above turbulent effect establishment and maintenance of optical link between the satellite terminal and ground terminal, and the PAT system must overcome effects of the turbulence on the optical link in satellite-to-ground optical communications. Currently, the detail about the effect of the turbulence on PAT technology is mainly concentrated on the Kolmogorov turbulence and Non-Kolmogorov turbulence model for research of the analysis of the relevant conclusions and the influence of atmospheric turbulence on the ground-satellite laser communications. In this dissertation, it is concerned with the atmospheric turbulence, effects of the joint turbulence on PAT technology, and corresponding compensation technology.In this paper, we firstly introduce the development of ground-satellite, the research on the atmospheric turbulence effect, and the influence of atmospheric turbulence on PAT system. It is included that the impact of atmospheric turbulence effect on pointing, acquisition and tracking system and the effect of atmospheric turbulence on the ground-satellite laser communications in the optical communication carrier of laser propagation of the atmospheric turbulence. And we had carried on the comprehensive analysis. Secondly, based on Non-Kolmogorov turbulence model, under the condition of moderate-strong fluctuations, the angle-of-arrival fluctuations in atmospheric turbulence effect are analyzed in theory, then we derived the angle-of-arrival fluctuations variances and temporal-frequency spectrum expressions, and the numerical simulation analysis are carried on. According to the actual situation of ground-satellite laser communications link, it has been built a two-layer model by the strong joint of atmospheric turbulence, so this model is applicable to the entire ground-satellite laser communications link, and with the basis of the theory model by using the modified Rytov approximation method, under the condition of joint atmospheric turbulence, the angle-of-arrival fluctuations are analyzed in theoretical level, then we derived the angle-of-arrival fluctuations variances and temporal-frequency spectrum expressions in the model of joint atmospheric turbulence, and the numerical simulation analysis are carried on.from the level of theory research and analyses the influence of atmospheric turbulence effect star to the influence of the optical communication link target capture tracking performance. The research work of this paper for PAT system design and the realization and optimization of concrete plans to provide the conditions of theoretical and experimental research.It will certainly to our country in space optical communication on the extensive development of pointing, acquisition and tracking technology to create for us a solid theoretical basis in the future.