为了研究星地下行激光链路接收光强起伏的统计特性,进行了恒星观测实验,分析了下行传输孔径接收下实际接收光强起伏的归一化方差、概率密度和闪烁频谱,并讨论了接收端瞄准偏差对接收光强的影响和星地下行大气信道的传播特性。实验结果表明,在下行传输孔径接收的条件下,天顶角从0°增至55°时接收光强的归一化方差从0.015增到0.102,不同天顶角下的接收光强起伏概率分布均服从对数正态分布,稳定大气条件下闪烁频谱的高频幂指数为-5/3,不稳定大气条件下为-11/3。

The irradiance scintillation of star was experimentally measured for studying the irradiance scintillation statistics for satellite-to-ground laser communication. Statistical properties of the irradiance scintillation for star, such as the normalized irradiance fluctuation variance, the intensity probability distribution function (PDF), and the power spectrum of atmospheric scintillation were analyzed. The influences of receiver pointing error on the intensity fluctuation and the propagation characteristic of atmospheric channel for satellite-to-ground laser communication were discussed. The measured results showed that with downlink propagation and aperture receiving, the normalized intensity scintillation variance ranged from 0.015 to 0.102 with zenith increasing from 0° to 55°, the PDF of intensity was accorded with lognormal model at different zenith, and the power-law value of high-frequency spectrum was -5/3 for steady atmosphere and -11/3 for unsteady atmosphere.