基于定标器相位梯度提取的圆迹SAR轨迹重建方法

Circular SAR Trajectory Reconstruction Based on Phase Gradient of Calibrators

圆迹合成孔径雷达(CSAR)高分辨率成像,对惯导系统的精度和稳定性提出了更高的要求,运动补偿技术是关键技术之一。该文首先分析了轨迹测量误差引起的相位误差,然后针对相位误差的空变性给出一种基于定标器相位梯度提取的圆迹SAR轨迹重建方法。该方法从SAR回波数据中提取定标器沿方位向的相位梯度,结合多个定标器的相位梯度,利用三边测量法重建高精度圆迹SAR轨迹,用于获取高质量的CSAR图像。该方法解决了轨迹测量误差引起的图像散焦问题,可实现整个场景的有效聚焦。仿真结果验证了该方法的正确性和有效性。

Circular SAR （CSAR） high resolution imaging requires a more accurate and stable Inertial Navigation System （INS）, therefore motion compensation is one of the key technologies. In this paper, the phase error caused by trajectory measurement error is firstly analyzed. Then, the CSAR trajectory reconstruction algorithm based on the extraction of calibrators＇ phase gradient is proposed. This algorithm is aiming at the spatial variant property of phase errors. The azimuth differential phase of each calibrator is extracted from SAR echo data. The high precision CSAR trajectory is reconstructed via trilateration in combination with multiple calibrators＇ phase gradient. The high quality CSAR image is formed with this trajectory. The proposed algorithm solves the problem of image defocusing by trajectory tt error, meanwhile the entire scene gets focused efficiently. The simulation results verify the correctness and effectiveness of the proposed algorithm.