The Research On Laser Spot Distributing And Orientation Of Detection System In Satellite Optical Communications With The Existence Of Atmospheric Turbulence

Laser satellite communications are considered as the important evolution of satellite communication technology. Over conventional microwave communications, it holds potential advantages of a larger capacity, higher data rate, less mass, less power, smaller antennas, less volume and lower probability of intercept. The study of laser satellite communications has presently become an important research domain.Laser satellite communications include laser intersatellite communications and laser satellite-ground communications. Laser satellite-ground communications are key components for laser satellite communications. When the optical beam propagating in the atmosphere, atmospheric on flows of the different scale produce the optical refraction and diffraction, which results in turbulent effects, such as angle-of–arrival fluctuation, atmospheric scintillation, image aberrance, beam spreading and beam wander. The atmospheric turbulence induces refractive stochastic fluctuation, which conduce stochastic variety of laser beam field and seriously deteriorates laser beam propagation quality. The performance and reliability of laser satellite-ground communication systems are affected by atmospheric turbulence. So this paper is concerned with study on effect of atmospheric turbulence on the characteristics of laser spot and identification algorithm.Firstly, the research status of satellite optical communication is summarized in this paper, and the research actuality and development for effects of atmospheric turbulence on PAT technology in the world are summarized. The phenomena of atmospheric turbulence are introduced. The physics model and optical statistic characteristic of atmospheric turbulence are stated. The characters of laser satellite-ground communication links have been analysed, and the formulae of mean receiving power is given. Meanwhile, the paper analyzed the properties of spot on the accepting plane from theory and computer simulation, especially studied on effect of atmospheric turbulence on the characteristics of laser spot. Far field distribution of Gaussian beam, probability density function, scintillation index of the received intensity, and laser spot centres are researched based on the analysis of the experimental data. Finally, this paper tries to improve its location accuracy from finding a good arithmetic. The wavelet filter for Bayesian estimates that one of the denoising methods was discussed, and a method to improve the location accuracy by improved Otsu was presented. The simulation showed that the proposed method made the centric error less than before. This conclusion can be good for the further research.