基于高次余弦散射分布的空间卫星可见光特性

基于几何光学和辐射理论,研究了空间卫星的可见光散射特性.空间卫星的背景辐射主要包括太阳的直接辐射和地球及大气的散射辐射,根据目标的结构特性与背景特性建立了空间卫星的几何模型和光照模型.分析目标表面状况,入射到目标表面的光线近似服从高次余弦散射分布,根据能量守恒定理及表面材料的高次余弦散射分布特性建立了目标散射特性的数学模型.通过矢量坐标变换确定太阳、地球、观测卫星在目标本体坐标系下的相对位置关系.根据给定的几何尺寸和表面物性参量仿真获得了目标在探测器入瞳处的能量分布及星等特征,目标本体与太阳帆板在探测器入瞳处的辐照度最大量级均为10-12 W/m2.仿真结果表明太阳帆板在目标特性分析时不可忽略,为空间目标的可见光探测提供参考数据.

Visible Characteristics of Space Satellite Based on Nth Cosine Scattering Distribution

Visible scattering characteristics of a space satellite are studied based on geometrical optics and radiation theory. The background radiation of the space satellite consists of direct solar radiation and scattered radiation of the earth and atmosphere. Geometrical and illumination models of the space satellite are established according to target structure and background characteristics. Target surface appearance is analyzed and the ray incident to target surface follows a Nth cosine scattering distribution approximately. A mathematical model of target scattering characteristics is established in terms of energy conservation law and Nth cosine scattering distribution properties of surface material. The relative position of the sun, the earth and the observation satellite in target body coordinate system is determined by vector coordinate conversion. Energy distribution and magnitude characteristics on the entrance pupil of the detector are simulated by its given physical dimension and surface physical parameters. The maximum magnitude of irradiance from target body and solar sail on the entrance pupil of the detector is 10-12 W/m2. Simulation results indicate the solar sail cannot be neglected when the target characteristics are analyzed and it can provide reference data to visible detection of space targets.