基于双向反射分布函数的卫星表面光散射研究

Researches on the Light Scattering Properties of Satellite Based on the Bidirectional Reflectance Distribution Function

基于双向反射分布函数（BRDF）,从太阳辐射理论出发,分析了表面漫反射率与入射波长的关系,卫星、太阳及观测站三者的相互位置关系。推导了卫星表面为朗伯表面和以BRDF模型为基础的随机粗糙表面的散射光照度表达式。然后以FY-1D卫星为例,计算了一段观测时间内,卫星地面照度值和视星等值的变化情况。最后比较了这两种条件下的地面光照度值,结果表明,把卫星表面看作漫散射体得到的地面照度值要比把卫星表面看作随机粗糙表面得到的地面照度值大。

Based on the bidirectional reflectance distribution function（BRDF） and the basic radiation theory,the relations of the diffuse reflectance and the incident wavelength,and the position relations of the satellite,the sun and the observation point are analyzed.Based on the BRDF model,the formulations of the illuminance of the scattering light on the randomly rough surface are derived.And the result shows that the surface of the satellite is the Lambert surface.Subsequently,take FY-1D satellite for example,in observation time,the changes of the ground irradiance and the magnitude of FY-1D satellite are calculated.Finally,the illuminace values at two conditions above are compared.It is found that the illuminance value calculated by assuming the satellite surface as a diffuser is larger than that as a randomly rough surface.