星地链路激光通信地面站址选择及大气影响研究

Atmosphere Impact and Ground Station Selection for Satellite-to-Ground Laser Communication

综合考虑我国方量的地理分布和气候特点,提出了一项星地激光通信的地面多址布站方案,仿真分析了大气散射引起的衰减及大气湍流对星地链路的影响。利用卫星工具包(STK)软件分析了地球静止轨道(GEO)卫星与5个地面站的链路特性。结果表明,西藏的阿里站同时具有最理想的经度和纬度,地平角为52°,最有利于开展星地激光通信。在一定天气条件下,随着波长的增加,对应的散射引起的功率衰减减小;随着能见度的降低,大气散射引起的光功率平均衰减增加;随着地平角的升高,大气引起的功率平均衰减减小;波长越长,闪烁指数越小;随着接收孔径直径的增大,闪烁指数快速减小;随着海拔高度的增加,闪烁方差减小。该研究为星地激光通信外场实验提供了一定的理论依据。

A multiple ground stations scheme satellite-to-ground laser communication is proposed with the geographical distribution of cloud cover and climatic features considered. The effect of attenuation caused by atmospheric scattering and atmospheric turbulence is analyzed for different paths from geosynchronous earth orbit （GEO） satellites to five ground stations. Link characteristics between the GEO satellite and the five ground stations are simulated using the satellite tool kit （STK） software. The results show that All region in Tibet has the best longitude and latitude conditions with a horizontal angle of 52°, which is most beneficial to laser satellite- to-ground communications. The power attenuation shows a decreasing trend as the wavelength increases due to scattering under the same weather conditions. The optical power attenuation is intensified as visibility falls. The average power attenuation caused by atmosphere decreases along with the rise of horizontal angle. The longer the wavelength A, the smaller the scintillation index; the scintillation index decreases rapidly when the diameter of receiving aperture increases; the scintillation variance is improved as altitude increases. The analysis is helpful with field experiments of satellite-to-ground laser communication.