SAR振动目标成对回波聚焦的改进Keystone变换算法

Improved Keystone Transform Algorithm For Paired Echoes Focusing of SAR Vibrating Targets

  • 摘要: 在高分辨率SAR成像中,成对回波是振动目标典型的多普勒特征,常规聚焦成像算法处理后会出现散焦现象,不利于对目标振动参数的分析。本文提出了一种振动目标成对回波的聚焦算法。在推导振动目标二维频域解析式基础上,采用Keystone变换进行徙动校正,接着在距离-多普勒域中完成二次相位误差补偿,实现了振动目标与静止目标的同时聚焦。该方法不需要振动目标先验知识,适合对不同振动状态下多目标成对回波的聚焦,点目标仿真验证了算法的有效性

     

    Abstract: Paired echoes are the typical Doppler characteristics of vibrating targets in high resolution synthetic aperture radar (SAR). Conventional imaging algorithms produce smeared paired echoes which is not conductive to the analysis of vibrating parameters. A paired echoes focusing algorithm for vibrating targets is proposed. On the basis of the analytic formula derivation in 2-D frequency domain for vibrating targets, Keystone transform is employed to perform migration correction. Then the quadratic phase error is compensated in the Range-Doppler domain. Finally, the vibrating targets and the stationary targets can be well focused contemporaneously. The proposed algorithm needs no prior knowledge of vibrating targets, so it can be used for the imaging of multiple targets at different vibrating state. The simulation results validate the effectiveness of the proposed algorithm.

     

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