基于STK的空间目标可见光散射特性建模与仿真

为给天基光学观测系统的设计和性能研究提供数据支持, 建立了基于STK的天基 探测空间目标等效星等计算模型. 选用双向反射分布函数(BRDF)五参量计算模 型, 分析了空间目标面元的可见光散射特性; 根据目标几何结构尺寸和物性参 量等建立目标几何模型, 对该模型进行面元划分, 推导了空间目标在天基观测 系统入瞳处的等效星等计算公式; 结合卫星工具包(STK)提供的太阳、目标卫 星、观测卫星三者的关系数据, 建立了基于STK的易于求解的目标星等计算模 型, 对此模型进行实例仿真和分析, 并与漫反射计算模型进行比较. 结果表 明BRDF模型得到的辐照度曲线比漫反射模型更曲折且存在峰值现象, 更符合 目标表面材料的实际特性, 此外, 与STK的结合运用, 使其可更加方便快捷地获得目 标最佳观测时段及相应的等效星等. 

Modeling and Simulation of Visible Light Scattering Properties of Spatial Object Using STK

For supplying the space-based optical observation system designer with referenced data, equivalent magnitude model of spatial object is established using STK. First, the visible light scatting characteristics of spatial object surface cell is analyzed by using BRDF five-parameter model. Second, combined with the characteristics of object shape and material property, the configuration model of space target is built, and formulation of equivalent magnitude computing model of space object is carried out by analyzing every single surface cell. Last, Satellite Tool Kit (STK) was used to provide relationship among sun, space object and observation satellite to simplify the solving of the formulation, and then, a new magnitude computing model based on STK is established. It was verified with one example and some analyses. The result displays that the new model is much more precise than the diffuse one. Besides, the results show that the best observing time and the corresponding magnitude can be easily solved with STK.