Generalization of Planar SAS to Irregular 2D Grid of a Top View Sonar

In top view 2D scan imaging, Planar Synthetic Aperture Sonar (PSAS) is a processing that takes advantage of the overlap of both ping-to-ping and track to track footprints to improve the imaging resolution in both directions. This is done by considering a perfect 2D regular grid of ping positions, which is not the case in real 2D scans due to trajectory disturbance and/or spatial undersampling. A Generalized Planar SAS (GPSAS) approach is proposed in this paper to circumvent the non-regularity of the grid of pings. This processing is applied directly to pings in their own “irregular” positions by synthetizing planar antennas centred at new sonar positions (real or fictitious), and then generating a new “virtual” regular grid of processed data. Simulation and in-tank laboratory experiment are conducted to illustrate and evaluate the proposed PSAS technique.