中法海洋卫星散射计噪声分析及自适应估计

Noise Analysis and Adaptive Estimation of CFOSAT Scatterometer

针对星载扇形波束扫描散射计数据预处理中噪声能量估计问题,对中法海洋卫星(China-France oceanography satellite,CFOSAT)微波散射计数据稳定性及其对噪声能量估计的影响进行了分析,基于内部噪声信号和内定标信号构建了噪声能量估计的二元多项式模型,实现了散射计噪声能量的自适应估计。微波散射计数据预处理中需要由回波能量中去除噪声能量获得观测信号的能量,噪声能量的准确估计是获得高精度后向散射系数的前提。CFOSAT散射计数据验证表明,该方法在数据稳定性较差的条件下,也能够自适应地获得准确的后向散射系数,进而获得稳定、准确的海面风场反演性能。

In terms of the noise energy estimation in the data preprocessing of spaceborne fan-beam scanning scatterometer,the stability of CFOSAT(China-France oceanography satellite)data and its influence on noise energy estimation are analyzed.Based on the internal noise signal and internal calibration signal,the bivariate polynomial model of noise energy estimation is constructed,and the adaptive estimation of noise energy is realized.In the data preprocessing of scatterometer,the energy of the observation signal is obtained by removing the noise energy from the echo energy,and the accurate estimation of the noise energy is the premise of obtaining the high-precision backscattering coefficients.The validation on CFOSAT scatterometer data shows that the proposed method can adaptively obtain accurate backscattering coefficients even under the condition of poor data stability,and then obtain stable and accurate wind field inversion performance.