论述了太阳漫射板星上定标原理, 研究了太阳漫射板衰减监测方法。针对星上太阳漫反射板双向反射分布函数(BRDF)的衰变, 设计了以太阳为参照, 通过与星上漫反射板反射辐射量比对测量实现监测功能的多波段星上漫反射板衰减监测辐射计(SDDM)。介绍了星上定标与漫射板监测的关系, 设计了SDDM积分球两开口入光+挡板的光机结构, 消除了入射光角度变化与探测器响应的相关性。根据光机结构设置的监测过程, 给出了SDDM的监测物理模型, 并对SDDM滤光片探测器动态范围设置及信噪比进行了验证和分析。在实验室模拟了太阳照射SDDM太阳观测端口的角度变化, 对其透过率模型进行了多次重复测量, 结合漫射板相对双向反射比因子(BRF)测量不确定度、卫星姿态及漫射板安装误差进行分析, 得到SDDM测量的漫射板监测不确定度优于0.88%。

The principle of on-board calibration for a solar diffuser was expounded, and a method to monitor the degeneration of the solar diffuser was researched. A Solar Diffuser Degeneration Monitor(SDDM) was designed to monitor the degeneration of Bidirectional Reflectance Distribution Function(BRDF) of the solar diffuser by measuring the ratio of the reflected radiance of solar diffuser to sun irradiance. The relationship between on-board calibration and the monitor of the solar diffuser was described. An integrating sphere with two light imports and a baffle for the SDDM was designed to eliminate the dependence of the changed incident angles on the detector response. According to the monitor process, the physics models of SDDM were given, and the dynamic range and Signal to Noise Ratio(SNR) of detectors in the SDDM were validated and analyzed. Finally, the illumination of the sun on the SDDM was simulated in a lab to test the transmittance model repeatedly for several times. By analysis of the measurement uncertainty related to the Bidirectional Reflectance Factor(BRF) of the solar diffuser, satellite attitude and the mounting error of the SDDM, it shows that the monitoring uncertainty of the solar diffuser is better than 0.88%.