中文摘要：

为了分析太阳辐射对卫星光通信系统造成的影响,对GEO卫星和地面站通信时,外表面接收的太阳直接辐射进行理论分析,得出计算表达式;通过STK软件仿真分析了太阳直射对GEO和地面站通信时的可通率,仿真结果表明,当太阳-地面站与GEO夹角为3度且地面站为阿里时,太阳对GEO和阿里通信时的全年直射时间为1187分钟,可通率为99.7741。地面站为海南时,太阳对GEO和海南通信时的全年直射时间为1168分钟,可通率为99.7777。地面站为喀什时,太阳对GEO和喀什通信时的全年直射时间为1201分钟,可通率为99.7714。地面站为云南时,太阳对GEO和云南通信时的全年直射时间为1181分钟,可通率为99.7753。对地面站来说,太阳直射一般出现在北京时间的下午14：00-15：00之间。每次持续时间不超过30分钟。上述结果对建立可靠的深空通信链路具有十分重要的意义。

英文摘要：

The theoretical analysis on the outer surface of GEO satellites communications to ground stations in order to analyze the effect of solar radiation on satellite optical communication system caused by direct solar radiation,then the expression was evaluated. The available probability of the direct transit from sun to GEO and ground station communication was analyzed by STK and Matlab. The simulation results show that,the angle between the SEP（sun-earth-prober） is 3 degrees. The available probability for Ali ground station was 99. 7741 when the annual time of direct transit from sun to GEO is 1187 min. The available probability for Hainan ground station was 99. 7777 when the annual time of direct transit from sun to GEO is 1168 min. The available probability for kashi ground station was 99.7714 when the annual time of direct transit from sun to GEO is 1201 min. The available probability for yunnan ground station was 99. 7753 when the annual time of direct transit from sun to GEO is 1181 min. For the ground station,the direct transit time of the sun is generally appeared in the afternoon 14： 00-15： 00 of Beijing time. For the GEO,the direct transit time of the sun is generally appeared in the morning 2： 00-3： 00 of Beijing time. Each time of duration is no more than 30 minutes.