中文摘要：

利用半解析MonteCarlo方法，计算了星载激光脉冲水下光斑的分布状况，采用修正Henyey-Greenstein函数表示大气和海水信道的散射相位函数，计算结果表明：水下光斑的大小与卫星高度、水下深度及大气、海水的散射强度有关；在不考虑卫星与地球相对移动的条件下，水下300m深度光斑半径可达6km,发射机所发射光子仅有84％～88％能够到达水下接收平面；星载激光水下光斑分布不能视为大气和海水各自散射所引起光斑分布的简单叠加。

英文摘要：

Based on the semi-analytic Monte Carlo method, this thesis calculates the underwater spot distribution of space-borne laser pulse. A modified Henyey-Greenstein function is used to replace the scattering phase function of the atmosphere and the seawater. The results show the spot be decided by the satellite altitude, the depth, scatter intensity of atmosphere and seawater; Without regard to the relative move between satellite and submarine, the spot radius of 300m depth underwater is about 6km; The number of photons arrived the underwater receiving plan is about 84～88 percents of whole photons transmitted; The spot distribution of space-borne laser submarine communication don＇t equal to the sum of those resulted from atmosphere and seawater scattering severally.