基于子空间正交的阵列干涉SAR系统相位中心位置定标方法

Antenna Phase Center Calibration for Array InSAR System Based on Orthogonal Subspace

阵列干涉合成孔径雷达(Synthetic Aperture Radar,SAR)系统采用距离脉冲压缩、方位合成孔径和高度实孔径的方式,能够获得观测场景的3维SAR图像。在实际系统中多个通道的天线相位中心位置信息通常难以精确获得,如果不进行定标而直接进行成像处理将会造成高度维成像质量降低。针对天线相位中心位置定标问题,该文分析了天线相位中心位置误差对高度维成像造成的影响,提出了一种基于子空间正交原理的相位中心位置定标方法。该方法利用2维SAR单视复图像中的定标点数据,通过特征值分解得到噪声子空间,利用子空间正交原理同时求解多个通道对应的天线相位中心位置。针对阵列干涉SAR系统应用,该文给出了相位中心位置定标处理流程,最后通过仿真和实际数据处理验证了定标方法的有效性。

The array InSAR system obtains a three-dimensional image of an observed scene using a combination of pulse compression and synthetic and real aperture techniques. However, Antenna Phase Center（APC） errors can occur within a practical array InSAR system, which thus degrades the imaging quality in a height direction. The aim of this paper is to improve calibration problems occurring with APC errors. The effect of APC errors is analyzed, and a calibration method based on the orthogonal subspace principle is proposed that utilizes SAR Single Look Complex（SLC） to obtain the noise subspace through eigenvalue decomposition. The subspace orthogonal principle is then used to solve the APC positions of multiple channels simultaneously. In addition, a calibration scheme for the APC position is presented for application with an array InSAR system.The effectiveness of the proposed calibration method is verified using simulations and experimental results.