| 引用本文: | 贺雪莉，王晨沁，毛新华. 半盲二维自聚焦SAR运动目标成像方法[J]. 雷达科学与技术, 2019, 17(2): 124-130.[点击复制] |
| HE Xueli, WANG Chenqin, MAO Xinhua. SAR Moving Target Imaging Using Semi-Blind Two-Dimensional Autofocus Approach[J]. Radar Science and Technology, 2019, 17(2): 124-130.[点击复制] |
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| 摘要: |
| 在SAR对动目标成像时，由于目标运动的不确定性，针对静止目标的成像算法处理不能完全补偿由于目标运动引入的额外距离徙动（RCM）和方位相位误差（APE），因此，在SAR图像中，运动目标会出现二维散焦。已有方法都是针对残留距离徙动和方位相位误差分别进行估计和补偿，其补偿精度和计算效率还有待进一步改进。通过分析运动目标在SAR图像中的残留相位误差结构，提出一种针对运动目标散焦的二维自聚焦算法。新方法只需直接估计方位一维相位误差，然后利用先验的二维相位误差内部结构信息，将一维相位误差映射得到二维相位误差，从而实现精确的二维相位补偿。通过仿真实验验证了该方法在计算效率和估计精度上具有更明显的优势。 |
| 关键词: 合成孔径雷达 二维自聚焦 先验知识辅助 极坐标格式算法 |
| DOI：DOI:10.3969/j.issn.1672-2337.2019.02.002 |
| 分类号:TN957.51 |
| 基金项目:国家自然科学基金（No.61671240）；江苏省自然科学基金（No.BK20170091） |
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| SAR Moving Target Imaging Using Semi-Blind Two-Dimensional Autofocus Approach |
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HE Xueli, WANG Chenqin, MAO Xinhua
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College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China
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| Abstract: |
| Due to the uncertainty of targets motion, the range cell migration (RCM) and azimuth phase error (APE) of the moving target cant be completely compensated in synthetic aperture radar (SAR) processing. Therefore, the moving target often appears two-dimensional (2D) defocused in SAR images. The conventional 2D autofocus algorithms blindly estimate the phase error in the sense that they often suffer from low computational efficiency and lack of data redundancy to accurately estimate the 2D phase error. In this paper, a 2D autofocus method for refocusing defocused the moving target in SAR image is presented. The new method only requires a direct estimate of APE, while the residual 2D phase error is computed directly from the estimated APE by exploiting the analytical relationship between the 2D phase error and APE. The simulation experiment proved that the proposed approach offers clear advantages in both computational efficiency and estimation accuracy. |
| Key words: synthetic aperture radar two-dimensional (2D) autofocus prior knowledge aided polar format algorithm |
