现有的基于相位中心近似思想的多接收阵合成孔径声呐成像方法均忽略了非“停-走-停”和相位中心近似误差的方位向空变性影响,这在宽波束条件下可能导致图像出现几何失真,旁瓣升高以及图像对比度下降。针对这一问题,根据方位向侧视角与多普勒频率之间的一一对应关系,提出了一种兼顾补偿精度和实现效率的距离向时域分块一频域补偿的多接收阵合成孔径声呐宽波束成像处理方法,二维空域内开展的距离延迟误差分析定量说明了文中方法在高分辨合成孔径成像中的潜在优势。最后,采用仿真实验对这种宽波束情况下的潜在优势进行了验证,并利用实测数据进一步测试了这种方法的可行性。
Currently, nearly all multi-receiver synthetic aperture sonar (SAS) imaging methods based on phase center approximation (PCA) neglect the space-variance in azimuth related to the none" stop-and-hop" and PCA errors. Problems in wide-beam azimuth processing with conventional methods are the image geometric distortion, the increasing of the sidelobe level and the degrading of the image contrast owing to uncorrected residual system errors. To solve these problems, this paper made use of the one-to-one mapping relationship between the azimuth squint angle and Doppler frequency, and proposed a range time-domain division and compensation in frequency-domain imaging algorithm for wide-beam multi-receiver SAS, which considered the compensation precision and implementation efficiency simultaneously. The propagation range delay error in two-dimensional space domain quantitatively shows the potential capability for high resolution synthetic aperture image formation. Lastly, the simulated data sets are used to validate this potential capability in wide-beam case. Additionally, the feasibility of the presented method is tested through the real data sets.