全极化微波辐射计极化定标参数优化

Fully polarimetric radiometer polarization calibration parameter optimization

全极化微波辐射计能够通过极化定标源产生4个分量来测量Stokes参数。极化定标源由三极化定标标准的基础上,加上一个双轴相位延迟板来精确定标第四分量,从而实现对4个Stokes参数的定标。极化定标源通过旋转极化网格和相位延迟板的相对旋转角度可以产生出无数组不同的参考亮温矢量,产生定标观测矩阵,通过求解定标方程,可以得到未知增益和偏移量矩阵,进而可以求出定标误差,为后面的反演作为依据。本文主要工作是通过遍历找到一组合适的极化定标源参数角度组合,来使定标误差达到最小。通过仿真结果的比较,定标误差精度有明显的提高。

Fully polarimetric microwave radiometer measure the Stokes parametersproduced by the polarization calibration source. Polarization calibration soureeis facilitatedusing a biaxial phase-retarding microwave plate to provide aprecisely known fourth Stokes signal from the linearly polarized standard. Aceordingto rotatingpolarization grid and the phase retardation plate relative rotation angleean generate numerous different set of reference vectors brightness temperature and get the calibration observation matrix. By solving the calibration equations, we get the unknown gain and offset matrixand thus can be obtained calibration error for inversion. In this paperthe main work is to find a suitable set by traversing the polarization angle calibration source parameter combinations to make calibration errors to a minimum. By comparing the simulation results, the accuracy of the calibration error has been significantly improved.