基于CLEAN算法对一维综合孔径辐射计成像误差的校正

对于天线单元数较少的一维综合孔径微波辐射计,系统的采样基线数有限,导致辐射计对目标在空间频率域的采样产生截断,在成像结果中引起明显的吉布斯误差.实际应用中通常选择加窗函数来抑制吉布斯误差,但是加窗函数会降低辐射计系统的空间分辨率.为抑制一维综合孔径辐射计成像的吉布斯误差,提出了基于CLEAN算法的校正算法.针对目前已完成的8单元辐射计地面样机系统,通过仿真实验,验证了CLEAN算法对于抑制辐射计成像结果中吉布斯误差的有效性.

Gibbs Error Correction of the One-dimensional Synthetic Aperture Radiometer Based on CLEAN Algorithm

For the one-dimensional (1-D) synthetic aperture microwave radiometer with a small number of antenna elements, the system has a limited number of sampling baselines, which causes the truncated sampling in the special frequency domain, resulting in significant Gibbs errors in imaging results, and then affects the imaging quality of the synthetic aperture radiometer. In practical applications, the windowing function is usually chosen to suppress the Gibbs error, but the windowing function also reduces the spatial resolution of the radiometer system. Therefore, a correction algorithm based on CLEAN algorithm is proposed in order to suppress the Gibbs imaging error of the synthetic aperture radiometer. As an application, this method is implemented to a currently completed 8-element one-dimensional linear synthetic aperture radiometer ground prototype system, and the effectiveness of the CLEAN algorithm in suppressing the Gibbs error in the radiometer imaging results has been verified through a series of simulation experiments. In this paper, the basic principle of CLEAN algorithm is introduced in detail, and the effectiveness of the algorithm is verified by simulation experiments.