Range estimation of broadband noise sources in an ocean waveguide using the array invariant

Abstract

A method is developed for range estimation of broadband noise sources in a horizontally stratified ocean waveguide without a priori knowledge of the environment. It has previously been shown that the range of a transient source can be estimated using the ‘‘array invariant’’ method by analyzing instantaneous beam-time intensity data [Lee and Makris, J. Acoust. Soc. Am. 116, 2646 (2004)]. This method is now extended to range estimation of continuous, broadband noise sources in an ocean waveguide. It is shown that the cross-correlation of instantaneous beam-time intensity asymptotically reaches the array invariant. The range of the source can then be determined without knowledge of the environmental parameters. This method is applied to localize multiple uncorrelated noise sources in a horizontally stratified ocean waveguide without ambiguity.