Towed array beamforming during ship's maneuvering

Paulo and Sergio M. Jesus

Universidade do Algarve,
Campus de Gambelas, PT-8000,
Faro, Portugal.

Comments: download pdf file or with color figures pdf color .
Ref.: IEE Proc. Radar, Sonar and Navigation, vol. 143, no. 3, p. 210-215, 1996.

Towed hydrophone arrays are commonly used for determining the spatial characteristics of the underwater acoustic field. The assumption that the hydrophones lie in a straight and horizontal line is often made when beamforming the hydrophone outputs. However, due to tow vessel motion, ocean swells and currents the array adopts a nonlinear shape and the beamformer output is degraded. To estimate the positions of the hydrophones, an array was instrumented with a set of positioning sensors: compasses, tiltmeters, accelerometers and pressure gauges. This paper presents the array deformations recorded at sea when the tow vessel is turning and along straight line tracks. The influence of the observed deformations on the performance of the conventional beamformer output is discussed and ilustrated with simulated and real acoustic data.

ACKNOWLEDGMENT: this work was partially supported by the EU project MAS2-CT920022.