多普勒频谱模糊情况下的星载方位向多通道高分宽幅SAR-GMTI杂波抑制方法  

A Novel Clutter Suppression Approach for the Space-borne Multiple Channel in the Azimuth High-resolution and Wide-swath SAR-GMTI System with an Ambiguous Doppler Spectrum

作　　者：张双喜 乔宁 邢孟道[2] 吴亿峰 吴玉峰 ZHANG Shuangxi;QIAO Ning;XING Mengdao;WU Yifeng;WU Yufeng(School of Eletronics and Information,Northwestern Polytechnical University,Xi’an 710129,China;National Key Laboratory of Radar Signal Processing,Xidian University,Xi’an 710071,China;Leihua Electronic Technology Research Institute,Wuxi 214063,China)

机构地区：[1]西北工业大学电子信息学院,西安710129 [2]西安电子科技大学雷达信号处理国家重点实验室,西安710071 [3]雷华电子技术研究所,无锡214063

出　　处：《雷达学报（中英文）》2020年第2期295-303,共9页Journal of Radars

基　　金：国家自然基金(61801387);中国博士后科学基金(2019M653741);航空科学基金(ASFC-20172053018)。

摘　　要：该文提出了一种在多普勒频谱模糊情况下的星载方位向多通道高分宽幅合成孔径雷达地面运动目标检测(SAR-GMTI)系统的杂波抑制方法。首先,利用方位解线性调频对方位向多通道(HRWS)SAR-GMTI系统中的回波进行处理,得到杂波和动目标的粗聚焦图像。然后,将多通道SAR系统的粗聚焦图像表示为矩阵形式,并估计出相应的协方差矩阵。之后,用杂波协方差矩阵构造杂波空间的正交矢量,即最小特征值对应的特征向量。该方法需要一个冗余的通道自由度。由于杂波空间的正交矢量与杂波空间向量是正交的,因此可以用来抑制杂波。最后,通过仿真和实测数据实验结果验证该文所提杂波抑制方法的有效性。A low pulse repletion frequency is required and an ambiguous Doppler spectrum should be considered to obtain a high-resolution and wide-swath Synthetic Aperture Radar-Ground Moving Target Indication(SAR-GMTI) system in the azimuth direction. In this study, we have proposed a novel clutter suppression approach, where the Doppler spectrum of the single channel echo is ambiguous, with respect to the space-borne multiple channels in an azimuth high-resolution and wide-swath SAR-GMTI system. Initially, the azimuth deramping operation is utilized to compress the ambiguous Doppler spectrum, where the signal of clutter or the moving target is focused toward only some azimuth Doppler-frequency bins. Further, a covariance matrix corresponding to the clutter is estimated in the azimuth deramping and range compression domain.Subsequently, the matrix eigenvalue decomposition technique is employed to obtain an eigenvector corresponding to the minimum eigenvalue. Herein, we intend to achieve redundant channel freedom to ensure the suppression of clutter. The obtained eigenvector can be considered to be the orthogonality vector of the clutter space, which denotes the orthogonality with respect to the signal space vector. Hence, we adopt the obtained eigenvector to appropriately suppress the clutter. Simultaneously, the signal of the moving target can be appropriately preserved. Finally, some experiments are conducted to validate the proposed clutter suppression approach.

关 键 词：星载方位向多通道合成孔径雷达 杂波抑制 高分宽幅(HRWS) 方位解线性调频 正交矢量 

分 类 号：TN95[电子电信—信号与信息处理]