Displaced phase center array (DPCA) and along-track interferometry (ATI) have been widely used for ground moving target indication (GMTI) in multi-channel circular synthetic aperture radar (CSAR) system. In ideal conditions, these methods can suppress background clutter effectively. However, the nonideal movement of platform may create a nonzero crab angle, which will induce a cross-track baseline offset and affect GMTI processing seriously. This letter analyzes the influence of crab angle on interferometric phase theoretically. Here, we propose a two-step phase calibration method to greatly improve the performance of CSAR-GMTI by eliminating the range-varying phase error. This method is independent of imaging and GMTI processing. Simulated and measured data results verify the correctness of the theoretical analysis and the validity of the proposed method.

中文翻译：

---

双通道CSAR-GMTI处理的新相位校准方法

位移相位中心阵列（DPCA）和沿航迹干涉（ATI）已广泛用于多通道圆形合成孔径雷达（CSAR）系统中的地面移动目标指示（GMTI）。在理想条件下，这些方法可以有效抑制背景杂波。然而，平台的非理想运动可能会产生非零偏航角，这将导致跨航迹基线偏移并严重影响 GMTI 处理。本文从理论上分析了偏斜角对干涉相位的影响。在这里，我们提出了一种两步相位校准方法，通过消除范围变化的相位误差来大大提高 CSAR-GMTI 的性能。该方法独立于成像和 GMTI 处理。