Imaging Algorithm for Multireceiver Synthetic Aperture Sonar

This paper presents a range migration algorithm for the multireceiver synthetic aperture sonar (SAS) based on Loffeld's bistatic formula, which consists of the quasi monostatic term and the bistatic deformation (BD) term. It is expected that the multireceiver data can be easily focused by the monostatic SAS imaging algorithm after compensating the BD term. In this paper, the BD term is first decomposed into the range variant phase and the range invariant phase. At this point, the BD term is compensated via two steps. One step is the compensation of the range variant phase through the range-dependent sub-block processing in the 2-D frequency domain. The other one is the arrangement of the multireceiver data in a sequential order in the 2-D time domain. After these operations, we obtain the monostatic SAS equivalent data, which is viewed as the input of the traditional range migration algorithm. The processing results of the simulated data and the real data show that the proposed method can work well for the focusing of the multireceiver SAS data. More importantly, the presented method dramatically improves the imaging efficiency without loss of performance since the complex multiplication and the data arrangement are only exploited by the presented method.