Research on Synthetic Aperture FM-CW Imaging Radar Utilizing Polarimetry

本研究旨在利用电磁波的全矢量性，即雷达极化特性，研制一种二维合成孔径FM-CW雷达。本研究的主要目的是将雷达极化原理引入宽带调频连续波雷达成像中。单色波的雷达极化测量已经建立，但如何将其融合到FM-CW雷达所处的宽手雷达信号中仍是一个问题。作者指出，在FM-CW雷达系统中获得的拍频频谱可以作为一个散射矩阵元素来替代，它在雷达极化测量中起着重要的作用。由于合成孔径信号处理后的拍频频谱具有复杂的幅度(幅度和相位)，承载着极化目标的信息，因此它代表了目标与极化有关的散射特性。详细研究了目标特有的特征偏振态以及二维FM-CW雷达成像原理。利用两个线性正交放置的目标进行了实验室测量，证实了FM-CW雷达是一个全极化成像雷达系统。

This research aimed at developing a 2-dimensional synthetic aperture FM-CW radar utilizing the full vector nature of the electromagnetic waves, i.e., radar polarimetry. The main purpose of this research was to introduce the principle of radar polarimetry into wide-band FM-CW radar imaging. The radar polarimetry has been well established for the monochromatic wave, however, there still remains a question how to incorporate it into a wide hand radar signal for which FM-CW radar resides. The authors pointed out in this research that the beat spectrum obtained in the FM-CW radar system could be replaced as a scattering matrix element which plays an important role in radar polarimetry. Since the beat spectrum after synthetic aperture signal processing has a complex amplitude (magnitude and phase) bearing polarimetric target information, it represents scatttering characteristics of a target depending upon polarization. The authos investigated the characteristic polarization states which are specific to a target in detail as well as the 2-dimensional FM-CW radar imaging principle. Using two linear orthogonally placed targets in a laboratory measurement, it is confirmed that the FM-CW radar acts as a full polarimtric imaging radar system.