A Novel Multireceiver SAS RD Processor
A receiver-by-receiver-based imaging algorithm that relaxes the requirement for the sub-block width and is successfully avoided by ghost targets, which are successfully avoided by presented method with the same wide sub-block.
Abstract
Classic multireceiver synthetic aperture sonar (SAS) reconstruction algorithms relying upon Loffeld’s bistatic formula (LBF) should first utilize the data segmentation approach to remove the multireceiver deformation (MD) term. Usually, the small sub-block is required by traditional LBF-based imaging algorithms to produce high-performance results. To address this issue, we describe a receiver-by-receiver-based imaging algorithm. The presented method first reformulates the original LBF to range dependent and independent terms. Then, the image reconstruction receiver-by-receiver is carried out. The LBF reformulation and the quadratic expansion of range-dependent term needed by subsequent range-Doppler (RD) algorithm would generate approximation error corrected by the data segmentation approach in the frequency domain. After performing the range cell migration correction (RCMC) receiver-by-receiver, the signal in the RD domain related to each receiver is coherently synthesized, and the azimuth offset is thereafter corrected. The focusing result would be produced when the azimuth inverse Fourier transform (IFT) is completed. On the basis of simulation and real data test experiments, conventional focusing approach with wide sub-block is seriously affected by ghost targets, which are successfully avoided by presented method with the same wide sub-block. It indicates that the presented method relaxes the requirement for the sub-block width.