| 摘要: |
| 距离模糊和方位模糊会严重影响星载合成孔径雷达（Synthetic Aperture Radar,SAR）的成像质量。现有的利用天线波束赋形来抑制模糊的方法在雷达正侧视成像时取得了优异的效果，但并不适用于雷达斜视的情况。针对这一问题，提出了一种基于平面阵列天线波束赋形的星载SAR二维模糊（距离和方位模糊）抑制方法。使用距离-方位模糊综合的模糊比（Ambiguity to Signal Ratio,ASR）指标来替代距离模糊比及方位模糊比，结合对不同斜视情形下天线波束变化的分析，充分考虑包含镜像模糊区在内的所有模糊区，建立了模糊比-天线权重优化模型。以模糊能量为目标函数、天线方向图掩模作为约束确立二次锥（Quadratic Cone Programming,QCP）优化问题，求解得到阵元幅度相位分布。仿真结果表明，所提方法可以通过调节模糊区对应的旁瓣幅值，灵活地抑制SAR斜视成像的距离和方位模糊，进而提高星载SAR的成像质量。 |
| 关键词: 星载合成孔径雷达 模糊抑制 天线方向图综合 波束优化赋形 |
| DOI：10.20079/j.issn.1001-893x.230118005 |
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| 基金项目:中国科学院青年创新促进会项目（2020123） |
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| Suppressing Range and Doppler Ambiguity by Optimal Beamforming for Squinted Spaceborne SAR |
| WANG Changcheng,ZHANG Yi,ZHANG Yongwei,WANG Wei |
| (1.Aerospace Information Research Institute,Chinese Academy of Sciences,Beijing 100190，China;2.School of Electronics,Electrical and Communication Engineering,University of Chinese Academy of Sciences,Beijing 100049,China) |
| Abstract: |
| The range and azimuth ambiguity often lead to deteriorated influence on the quality of the spaceborne synthetic aperture radar(SAR) images.The existing ambiguity suppression methods via antenna beamforming get excellent effect in the radar broadside imaging mode,but cannot work well in squinted case.To deal with this problem,a method based on planar array antenna pattern synthesis is proposed,which successfully suppresses both the range and azimuth ambiguity.First,to substitute the range ambiguity to signal ratio(ASR) and azimuth ambiguity to signal ratio,the ASR is introduced.Next,by analyzing the antenna beam in squinted SAR,an ASR-array weight optimization model is proposed which consideres all ambiguity areas including mirrors.Then,the quadratic cone programming(QCP) problem is built to minimize the ambiguity energy under the antenna mask constraints.Further,the array amplitude and phase distribution can be accordingly acquired by solving this problem.The simulation results show that the proposed method can flexibly reduce the range and azimuth ambiguity energy of squinted SAR by adjusting the sidelobes in ambiguity areas,thereby improving the imaging quality of spaceborne SAR. |
| Key words: space borne synthetic aperture radar(SAR) ambiguity suppression antenna pattern synthesis optimal beamforming |
