中文摘要：

利用半解析蒙特卡罗方法计算光子在地球大气和海水中传输的多径时间扩展效应，大气和海水信道的散射相位函数采用修正Henyey-Greenstein函数，根据标准大气数据对散射和衰减系数进行加权处理．结果表明：光脉冲在地球大气和海水中传输时的多径时间扩展与卫星高度、水下深度及大气和海水的散射强度有关；水下接收信号的平均多径时间扩展可达33．4～34．9μs，最大时间扩展可达160μs；星载激光对潜通信下行链路的多径时间扩展效应不能由大气和海水各自的多径时间扩展效应和表示．

英文摘要：

Individual photonls multipath effect when it travelling through atmosphere and seawater happens was calculated by using semi-analytic Monte Carlo method. A modified Henyey-Greenstein function was used to represent the scattering phase function of the atmosphere and sea. Based on the L. Elterman hierarchical model, the scattering and attenuation coefficient was weighted according to the standard atmospheric data. The results show the multipath temporal spreading he decided by the satellite altitude, the depth, scatter intensity of atmosphere and sea. The average temporal spreading of underwater received laser pulse can be about 33.4-34.9 μs. The maximum spreading is about 160 μs. The multipath temporal spreading of space-borne laser submarine communication downlink can not be considered as the sum of temporal spreading result from atmosphere and seawater respectively.