大气弱湍流下星地光链路衰落特性影响因素分析

研究了弱湍流条件下星地光通信链路的衰落概率、平均衰落次数以及平均衰落时间3个重要参数的统计特性，并通过数值仿真分析了链路天顶角、光波长以及接收机海拔高度对链路衰落特性的影响。结果表明:减小天顶角和提高接收机探测灵敏度可以改善链路的衰落特性；1.55 m激光较0.85 m、1.06 m激光更适合于星地光通信；地面接收机应尽量建在2 000 m以上的高海拔地区。

Influencing factors on fading characteristic of satellite-to-ground optical communication link in weak atmospheric turbulence

The statistical characteristic of the three important factors which are fading probability, mean fading number and mean fading time of satellite-to-ground optical communication link subject to weak atmospheric turbulence is researched, and the influence of zenith angle, light wavelength and altitude of receiver on the satellite-to-ground laser link is analyzed by numeric simulation. The result of research shows either decreasing the zenith angle or increasing the detection sensitivity of receiver can improve the fading characteristic of laser link; the 1.55 μm laser is more suitable for satellite-to-ground optical communication than 0.85 μm and 1.06 μm; the receiver should be established in the region with altitude higher than 2 000 m.