A New Back-projection Algorithm in Frequency Domain for Multi-receiver Synthetic Aperture Sonar

Abstract

This paper proposes a new back-projection algorithm (BPA) based on the phase shifting in the frequency domain for multi-receiver synthetic aperture sonar (SAS) using linear frequency modulated (LFM) signal. With the consideration of the change of sound velocity in the depth, the Doppler effect, and the use of linearity property of inverse Fourier transform (IFT), the proposed BPA can improve the SAS image quality and reduce the computation time compared to the conventional BPA in the frequency domain. The improvements of the SAS image quality are represented by enhancing position accuracy, along-track resolution, the peak sidelobe ratio (PSLR), and signal/noise ratio (SNR). The merits of the proposed BPA are evaluated by comparing the simulation results from the proposed BPA and the conventional BPA with the sound velocity profile (SVP) in Vietnam’s sea.