星载多角度偏振成像仪测量精度验证与偏差分析

Measurement Precision Verification and Deviation Analysis of Spaceborne Directional Polarimetric Camera

为了检验星载多角度偏振成像仪(DPC)在自然目标下的偏振和辐射定标精度,设计了测量精度验证试验。在晴朗天气对天空成像,得到了天空的偏振度和辐亮度数据,并将其与同时观测的CE318型太阳-天空偏振辐射计的数据进行了比对。结果显示:三个偏振波段的平均偏振度差异小于0.02,满足DPC偏振测量精度的指标要求,但辐亮度差异较大。修正定标光源与测量目标间光谱非匹配的影响,两台仪器观测波段、观测视场非一致性的影响以及系统偏差后,两台仪器490nm和670nm通道的平均辐亮度的差异小于1%,865nm通道的平均辐亮度差异小于2%,验证了DPC定标数据的有效性和仪器的测量精度。

In order to verify the polarization and radiation calibration precision of the directional polarization camera（DPC）under natural targets,a verification experiment of measurement precision is designed.The data of the degree of polarization and radiation luminance for sky are obtained by imaging the sky in a clear weather and these data are compared with the simultaneous observation data by the CE318 sun-sky radiometer.The results show that,the average difference of the degree of polarization for the three polarization bands is smaller than 0.02,which meets the requirements of the polarization measurement precision of DPC,but the radiation luminance difference is big.After the correction of system deviation,the effect of the spectral non-matching between the calibration light source and target,and the effect of the inconsistency of the observation waveband and the observation visual field of two instruments,the average difference of radiation luminance for 490 nm and 670 nm channels of two instruments is less than 1%,and for the 865 nm channel is less than 2%,which verifies the validity of calibration data of DPC and the measurement precision of instruments.