结合偏航校正的合成孔径声呐大测绘带运动补偿方法

Synthetic aperture sonar wide-swath motion compensation method combined with yaw correction

传统基于频域补偿相位的运动补偿方法难以校正姿态误差造成的波束照射方向偏转,因此提出了一种基于偏航校正的合成孔径声呐大测绘带运动补偿方法。首先,利用时延的距离空变特性校正时延估计野值,提高估计精度和稳健性;其次,通过在后向投影算法的成像过程中对实孔径成像网格进行旋转来校正偏航造成的波束照射方向偏转;最后,通过分段二维轨迹估计和分段成像克服运动误差的距离空变特性,实现大测绘带运动补偿。仿真结果表明,所提方法能够有效抑制偏航误差导致的点目标图像主瓣展宽、旁瓣升高和模糊现象。实验结果表明,相比于参考方法,所提方法在小偏航角和大偏航角条件下均显著提高了成像质量,有效校正了偏航造成的运动误差,实现了大测绘带精确成像。

The traditional motion compensation methods based on phase compensation in frequency domain are difficult to correct the beam steering caused by attitude errors.To solve this problem,a yaw correction based wide-swath motion compensation method for synthetic aperture sonar is proposed.Firstly,the range-varying nature of time delays is utilized to correct outliers in time delay estimation,thereby improving estimation accuracy and robustness.Secondly,the beam steering caused by yaw is corrected by rotating the real aperture imaging grid during the imaging process of the back-projection algorithm.Finally,the range-varying nature of motion errors is overcome through segmented two-dimensional trajectory estimation and segmented imaging,enabling wide-swath motion compensation.Simulation results show that the proposed method effectively suppresses the widening of the main lobe,elevation of sidelobes,and blurring of point target images caused by yaw errors.Experimental results demonstrate that compared to the reference method,the proposed method significantly improves imaging quality under both small and large yaw angles,effectively corrects motion errors caused by yaw,and achieves accurate imaging for wide-swath mapping.