The new concept of combining the azimuth multichannel synthetic aperture radar (SAR) system with the Scan mode was put forward to meet the requirements of future developments in high-resolution and ultrawide-swath SAR design. However, the phase imbalance between channels is inevitable, which will greatly reduce the quality of the image. This article proposed an approach of phase imbalance estimation for azimuth multichannel ScanSAR system. For this, the particularity of the target Doppler spectrum in Scan mode is analyzed firstly. Then, the theoretical derivation reveals the equivalence of scene ambiguity and Doppler spectrum ambiguity. Subsequently, the main idea of the proposed approach is to determine the index of the ambiguous component of the target in the Doppler spectrum by the sparse recovery method. The equivalent multichannel ScanSAR real measured data experiment demonstrates the effectiveness of the proposed approach. Compared with the estimation results of the signal subspace comparison method, the proposed method shows better performance. Finally, the details in the implementation process of the proposed algorithm are described by combining theoretical analysis with simulation experiments.

中文翻译：

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方位多通道ScanSAR系统的相位不平衡估计

提出了将方位多通道合成孔径雷达（SAR）系统与“扫描”模式相结合的新概念，以适应高分辨率和超广域合成孔径雷达设计的未来发展要求。但是，通道之间的相位不平衡是不可避免的，这将大大降低图像质量。本文提出了一种方位多通道ScanSAR系统的相位不平衡估计方法。为此，首先分析了扫描模式下目标多普勒频谱的特殊性。然后，理论推导揭示了场景歧义和多普勒频谱歧义的等价性。随后，提出的方法的主要思想是通过稀疏恢复方法确定目标的多义分量在多普勒频谱中的索引。等效的多通道ScanSAR实测数据实验证明了该方法的有效性。与信号子空间比较方法的估计结果相比，该方法具有更好的性能。最后，将理论分析与仿真实验相结合，详细描述了该算法的实现过程。