微波辐射计定标注入噪声特性分析与校正

摘要

Different from the satellite-based microwave radiometer,black body and noise source are generally built in the ground-based radiometer for multi-point calibration because of the absence of the background of the cold space. However,as the calibrating reference signal,the noise injection of the receiver is directly related to the calibration accuracy. This paper introduces the system structure of K band ground-based microwave radiometer and a nonlinear calibration method;The transfer model based on scattering parameters of network is built up to analyze the noise injection,the linear compensation method can be used to correct the noise injection from the analysis. The results of the experiments show that the method can make the noise injection error less than 1K.%与星载微波辐射计不同,地基微波辐射计由于没有宇宙冷空背景作为低温定标参考,通常在系统中利用内置黑体和噪声源耦合注入进行实时定标.但是,作为定标基准信号,接收机注入噪声的偏差直接影响辐射计的定标精度.本文着重介绍了一种K波段地基微波辐射计的系统结构和噪声注入非线性定标方法,并以网络散射参量为基础建立了辐射计噪声注入信号的传输模型,在对注入噪声进行理论分析的基础上使用线性补偿方法修正接收机的注入噪声值.实验结果表明,该方法能够校正接收机的注入噪声,使其偏差小于1K.