航空多角度偏振辐射计信噪比估算与测量

Estimation and measurement of signal-to-noise ratio for aviation multi-angular polarimetric radiometer

为精确评估航空多角度偏振辐射计的性能,分析了航空多角度偏振辐射计的信号与噪声,给出了估算其探测器信噪比的过程。介绍了航空多角度偏振辐射计的工作原理,推导了探测器信噪比与系统信噪比的估算表达式。结果显示:系统信噪比与强度信噪比成正比,探测器信噪比需求与偏振探测精度成反比,航空多角度偏振辐射计的探测器信噪比应不小于245,得到的结果弥补了一直以来偏振遥感仪器只计算探测器信噪比的不足。最后,根据推导的表达式,通过矢量传输模拟估算了用航空多角度偏振辐射计探测典型场景时的探测器信噪比与系统信噪比,并在暗室中利用积分球与偏振盒进行了测量。结果表明,航空多角度偏振辐射计各个探测器的信噪比均满足偏振探测的需求。

To estimate the performance of an Aviation Multi-angular Polarimetric Radiometer（AMPR）precisely,its signals and noise were analyzed and the estimation processing for signal-to-noise ratios（SNRs）were investigated.The working principle of the AMPR was introduced and the formulas to calculate the detector SNRs and system SNRs were inferred.It indicates that the system SNR is proportional to intensity SNR while the requirement of detector SNR is inverse proportional to the polarimetric accuracy.However,the detector SNRs of AMPR should not be less than 245.The results make up the shortcoming from the traditional method that the precision of the polarization remote sensing instruments depends only on the detector SNRs.Finally,the system SNRs and the detector SNRs in a typical scene simulated by vector radiative transfer were estimated with the inferred formulaand tested by a Spherical Integrating Source（SIS）and a polarization box in a dark laboratory.The results show that the SNRs of the AMPR detector meet the requirements of polarimetric detection.