Individual horizontal array elements as windows to estimating ship radiated noise signature lobing patterns

Abstract

A horizontal hydrophone array is typically beamformed to produce the directivity required to produce array gain and determine bearing to a contact of interest. For ships passing near an array each omnidirectional hydrophone also provides a number of discrete “look windows” at the ship from a range of received angles. By assembling similar look window angles and applying a propagation model to estimate transmission loss, a partial lobing pattern for the ship's radiated noise signature can be estimated. A 48-element bottom-mounted hydrophone array in the Canadian Arctic provides an opportunity to test this approach in a low ambient noise environment with a variety of passing ships.