全极化散射计极化失真误差校正方法

全极化散射计是一种新型微波散射计，可以同时测量目标的同极化和交叉极化散射系数.一方面能够解决传统散射计在海面风场反演中的风向模糊问题，提高海面风场测量精度，另一方面交叉极化散射系数可以有效提高海面风速测量范围，解决台风灾害监测和预报问题.利用全极化散射计数据进行高精度海面风场反演，首先需要解决全极化散射计系统极化失真误差导致无法准确测量目标不同极化散射系数的问题.本文基于全极化散射计信号模型推导了极化失真误差影响下极化散射系数模型，并对极化失真误差影响进行了定量分析.在极化散射系数模型基础上，通过引入海面散射特性假设和极化定标技术推导了极化散射系数校正模型.基于RADARSAT-2获取的不同区域海面全极化散射系数数据仿真误差影响下极化散射系数并利用该模型进行校正，结果表明该方法可以有效校正极化失真误差，显著提高极化散射系数测量精度. 

Efficient Correction Method for Polarimetric Distortion Error of Polarimetric Scatterometer

The full-polarization scatterometer is a new type of microwave scatterometer that can simultaneously measure the co-polarization and cross-polarization backscatter of the target. It can solve the wind direction ambiguity problem of the traditional scatterometer in the sea surface wind retrieval and improve the wind measurement accuracy. Moreover, the cross-polarization backscatter can effectively increase the sea surface wind speed measurement range and can be used for typhoon monitoring. High-precision sea surface wind retrieval using full-polarization scatterometer data first needs to correct the polarization distortion error of the full-polarization scatterometer system. To solve this problem, the polarimetric scattering coefficient model influenced by polarimetric distortion error is built based on the signal model of polarimetric scatterometer, and then the influence of polarimetric distortion error in quantitatively analyzed. Based on the polarimetric scattering coefficient model, some assumptions of ocean scattering characteristic and polarimetric calibration are introduced to establish the correction model of polarimetric scattering coefficients. Simulation data based on RADARSAT-2 polarimetric scattering coefficients of different sea region is corrected and results show that the proposed method can effectively correct of polarimetric distortion error and greatly improve the measurement accuracy of polarimetric scattering coefficients.