【摘要】 综合孔径微波辐射计是被动微波遥感发展的新方向。综合孔径技术利用了以小口径天线阵列合成大的观测口径的技术,解决了在较低频率时天线物理口径要足够大才能得到期望的空间分辨率的严重缺陷。土壤湿度和海水盐度是影响全球气候和水气循环的重要因素。这些参数一般是在L波段范围观测得到,综合孔径辐射计就是减少天线孔径和重量,并最终可以观测反演出这两个参数的一项新兴技术。综合孔径辐射计不同于全功率辐射计,它测量的是视场亮温分布对于天线阵中不同基线长度的可视度函数分量。它的系统主体是稀疏天线阵和多通道相关接收机。在实际应用中,要得到土壤湿度等参数的反演,较高的系统亮温分辨率以及亮温与测量量之间的准确对应是至关重要的,这即是定标工作要完成的任务。定标直接影响微波辐射图解译和判读的准确度,是实现定量化微波遥感的前提。针对一维综合孔径辐射计系统,给出了一种定标方案。其中分析了天线阵以及多通道相关接收机部分的定标,由得到的矩阵形式的空间频率响应信息推出了亮温图像的反演公式。更多还原

【Abstract】 Synthetic aperture microwave radiometer represents a new technology being developed for passive microwave remote sensing. Aperture synthesis uses interferometric techniques to overcome the limitations set by antenna physical aperture while working at lower frequency.Two of the key geophysical parameters are soil moisture and ocean salinity which require observations at long wavelengths and therefore large antennas. This technology provides a possible solution to balance the requirement come from spatial resolution measurement sensitivity and antenna size and weight.Differ from the total power radiometer, Synthetic aperture microwave radiometer measures the coherent products from pairs of antennas as a function of baselines and the target called visibility of the brightness temperature. Before the instrument getting into practical application, calibration must be done. It involves relating the output indication (visibility) to the brightness temperature at the input and improving the radiometric sensitivity.In this paper, calibration algorithms for a one-dimensional synthetic aperture microwave radiometer are presented. After individually analyzing the thinned antenna array calibration and multiple-channel receiver calibration, it also presents the image reconstruction formula of the instrument.更多还原