研究了午夜前后阳光照射对静止轨道三轴稳定对地观测光学系统的系统成像和系统热稳定性的影响。根据光学系统在静止轨道运行时的受照特点, 分析了直射入光学系统的太阳光能量, 推导出由外遮光罩高度, 形状及不同太阳倾斜角确定的无量纲数阳光抑制比K, 用以描述外遮光罩对视场外直射阳光的抑制能力并指导各种形状外遮光罩的高度设计。用Monte-Carlo方法编制通用程序计算了各种轮廓形状在不同太阳倾斜角下的抑制比K。在实例设计中取春秋分K=0.5作为设计依据, 外遮光罩的高度为底部轮廓东西轴长的1.8倍, 此时阳光由遮光罩底部轮廓进入光学系统的时间为3 h, 设计结果满足卫星载荷尺寸要求。

The affects of direct sunlights before and after midnights on the imaging quality and thermal stability of an earth observation optical system on geostationary satellite in space were investigated. According to the characteristics of solar heat flux on the geostationary orbit, the energy density of direct sunlight projecting to the optical system was analyzed and a dimensionless parameter named sunlight inhibitory ratio determined by outer baffle′s height ,shape dimension and sun inclination was deduced. It was used to describe the inhibitory ability of outer baffle in the optical system for the direct sunlight and also used as a design principle for the height of outer baffle. The program based on Monte-Carlo method was compiled to solve the sunlight inhibitory ratio of different shape outer baffles in different sun inclination scenarios. In a real design, the sunlight inhibitory ratio was selected to be 0.5 at equinox and the final outer baffle height is about 1.8 times of the east-west axis length of the outer baffle’s bottom side. This way, the incidence sunlight in the optical system from the baffle is three hours. The result satisfies the dimension requirements of satellite payloads.