Source level estimation of a monopole source at rest in the presence of multipath

Abstract

The problem of estimating the source level of a broadband cw monopole source in coastal waters using a vertical array of hydrophones was investigated. The statistics of the sound field in a particular coastal region were modeled. The medium was idealized as a wedge-shaped volume bounded by a pressure release surface and a lossy inclined plane. The transfer function between source and receiver positions was treated as a random process. The signals from the hydrophone array were processed to give an estimate of the source level of the sound source. The efficiencies of a number of estimators were analyzed including beamforming, focusing, and linear and log power averaging. The bias and standard deviation of each estimator were measured as a function of the number of elements in the array. A numerical model implemented on a computer and a sea test provided the data samples on which the statistics were based.