干涉式综合孔径微波辐射测量的统计分布模型

A statistical measurement of interferometric aperture synthesis microwave radiometers

建立了数字相关式综合孔径微波辐射计干涉测量的统计分布模型.在信号样本统计独立的假设条件下,基于复威沙特分布推导了归一化干涉幅度和干涉相位的概率密度函数的解析表达式.针对实际情况中毗邻样本相关性引起的模型失真问题,引入有效取样数因子对模型进行修正.提出了幅度矩量法估计有效取样数,根据干涉幅度的二阶矩进行计算,快速简便.实验结果表明,经过有效取样数修正后,干涉幅度和相位的概率密度函数与实测数据的直方图基本相符.

A statistical model based on the complex Wishart distribution is presented to characterize the interferometric measurements in digital synthetic aperture radiometers. Under the assumption that the successive samples are statistically independent, the probability density functions （PDFs） of the normalized interferometric amplitude and the interferometric phase are derived. The model becomes biased due to the statistical dependence of adjacent samples in practice. Compensation with an effective sample size can account for such imperfection. A fast method of amplitude moments is proposed to determinate a suitable value for the effective sample size, using the second moment of the interferometric amplitude. Experimental results indicate good agreement between the measured histograms and the theoretical PDFs of both the normalized interferometric amplitude and the interferometric phase, which are improved by the effective sample size.