西安电子科技大学学报

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一种抑制SAR图像中动目标干扰的方法

肖力1,2;李学仕1,2;孙光才1,2;邢孟道1,2   

  1. (1. 西安电子科技大学 雷达信号处理国家重点实验室,陕西 西安 710071;
    2. 西安电子科技大学 信息感知技术协同创新中心,陕西 西安 710071)
  • 收稿日期:2016-02-02 出版日期:2017-04-20 发布日期:2017-05-26
  • 通讯作者: 邢孟道(1975-), 男, 教授, 博士,E-mail: xmd@xidian.edu.cn
  • 作者简介:肖力(1991-), 男, 西安电子科技大学博士研究生, E-mail: mr_xiao_li@163.com
  • 基金资助:

    国家自然科学基金资助项目(61301292);空间测控通信创新探索基金资助项目(201509A)

Method to suppress moving targets in SAR images

XIAO Li1,2;LI Xueshi1,2;SUN Guangcai1,2;XING Mengdao1,2   

  1. (1. National Key Lab. of Radar Signal Processing, Xidian Univ., Xi'an 710071, China;
    2. Collaborative Innovation Center of Information Sensing and Understanding, Xidian Univ., Xi'an 710071, China)
  • Received:2016-02-02 Online:2017-04-20 Published:2017-05-26

摘要:

在高分辨率宽测绘带合成孔径雷达系统中,用传统的静止场景成像方法对存在动目标的回波数据进行成像,动目标在得到的合成孔径雷达图像中是散焦的,并且动目标会聚焦到错误的位置,同时,散焦的动目标会掩盖原本的合成孔径雷达场景.利用传统的空时自适应处理方法对合成孔径雷达图像中散焦的动目标进行抑制时,所需的空间自由度为场景中动目标的个数与脉冲重复频率欠采样数的乘积,这在实际中很难得到满足.为解决这一问题,提出了一种基于方位Deramp处理的空时自适应处理方法.该方法首先对合成孔径雷达回波数据进行方位Deramp处理,使得动目标在空时平面中是粗聚焦的,此时,抑制合成孔径雷达图像中的一个动目标只需要一个空间自由度.当合成孔径雷达图像中存在多个动目标时,提出了动态导向矢量的概念,它能有效地减少抑制合成孔径雷达图像中散焦动目标所需的空间自由度数目.

关键词: 高分辨率宽测绘带, 合成孔径雷达, Deramp, 空时自适应处理方法, 动态导向矢量

Abstract:

In the high-resolution wide-swath (HRWS) SAR system, the moving targets are usually smeared and imaged at incorrect positions in the resulting SAR image by utilizing the traditional stationary scene imaging processing. Moreover, these defocused moving targets may cover the stationary scene. The number of spatial degrees of freedom required for suppressing moving targets by the traditional space-time adaptive processing framework is equal to the number of the moving targets in the SAR scene multiplied by the PRF undersampling number. This requirement is hard to meet in practice. In order to overcome the above problem, a new space-time adaptive processing framework based on azimuth Deramp processing is proposed in this paper. Firstly, the moving targets are coarsely focused in the space-time plane through the azimuth Deramp processing. In this case, only one spatial degree of freedom is needed for suppressing one moving target. If there are multiple targets, it can effectively reduce the required degrees of freedom by utilizing the dynamic steering vector concept. Last, simulation results are provided to show the validity of the proposed method.