论述了太阳漫反射板星上反射率定标原理，建立了基于太阳漫反射板的星上反射率定标物理模型。太阳漫反射板双向反射分布函数（BRDF）会随时间发生衰减，是星上定标不确定度的主要来源，为此对监测太阳漫射板BRDF方法展开了研究。建立了中分辨率成像光谱仪（MODIS）太阳漫射板稳定性监测辐射计的监测物理模型，分析其在在轨性能评估中发现的问题。提出了一种积分球“双入光口+挡板”的光学结构，在保证功能实现的基础上简化了物理模型，减少了影响仪器不确定的因素。实验验证了该光学结构可防止太阳观测端口响应出现波纹。根据新光学结构的监测物理模型，参照目前国内对其相关参数的测试水平，对其监测不确定度进行了预估。结果表明，其监测不确定度可优于0.68%。

The theory of on-orbit reflectance calibration of the solar diffuser panel is expounded and the physical model of on-orbit reflectance calibration is established. As the precision of on-orbit calibration is affected mostly by the degeneration of the solar diffuser’s bidirectional reflectance distribution function(BRDF), the method of monitoring the degeneration of BRDF is discussed. According to the monitoring physical model of the solar diffuser stability monitor of the moderate resolution imaging spectroradiometer (MODIS) and the problem founded in the on-orbit performance evaluation, an optical structure of integrating sphere with two imports for light and a baffle inside is proposed. The parameters in its physical model are decreased and some factors that bring uncertainties are cut down while the function can be ensured. It is validated that the optical structure can prevent the sun view response from the ripple signal response in experiment. Based on the physical model of the new optical structure and the domestic testing level, the uncertainty of this system is estimated, and it can be less than 0.68%.