Implementation of a synthetic aperture processing scheme in a towed array sonar system

Abstract

This experimental paper is concerned with the implementation of a passive synthetic aperture processing scheme in a towed array sonar system. It addresses theoretical and practical concerns, and the experimental results suggest that the concept of a synthetic aperture towed array system complements the conventional beamformer’s processing results. The acoustic synthetic aperture technique, which has been considered in this study, is the ETAM algorithm [i.e., extended towed array measurements, J. Acoust. Soc. Am. 87, 158–171 (1989)]. Theoretical and experimental studies have shown that the above technique compensates the random phase fluctuations in the data that are introduced by the tow path. This results is an effective extension of the physical aperture of a deployed towed array and consequently provides improved angular resolution performance equivalent to a fully populated long array. Also included in this presentation is a discussion of the development of the computing architecture requirements related to this kind of implementation. It is shown that the development of a next generation signal processor (NGSP) by the Defence Research Establishment Atlantic (DREA) overcomes the limitations normally associated with the implementation of nonlinear algorithms into parallel FFT-based vector processors.