Near- and far-field beam forming using a linear array in deep and shallow water

• Published in: The Journal of the Acoustical Society of America Vol. 135; no. 4_Supplement; p. 2393
• Main Authors: Culver, Richard L., Fowler, Brian E., Barber, D. Chris
• Format: Journal Article
• Language: English
• Published: 01.04.2014
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.4877920

Underwater sources are typically characterized in terms of a source level based on measurements made in the free-field. Measurements made in a harbor environment, where multiple reflections, high background noise and short propagation paths are typical, violates these conditions. The subject of this paper is estimation of source location and source level from such measurements. Data from a test conducted at the US Navy Acoustic Research Detachment in Bayview, Idaho during the summers of 2010 and 2011 are analyzed. A line array of omnidirectional hydrophones was deployed from a barge in both deep and shallow water using calibrated acoustic sources to evaluate the effectiveness of post-processing techniques, as well as line array beamforming, in minimizing reflected path contributions and improving signal-to-noise ratio. A method of estimating the location of the sources while taking into account a real, non-linear array based on these measurements is presented. [Work supported by the Applied Research Laboratory under an Eric Walker Scholarship.]