Extracting waveguide parameters from the coherent field measured on a synthetic aperture horizontal array.

Abstract

For a time‐harmonic source in a stratified waveguide, the acoustic field can be approximated by a coherent sum of modes propagating in range. In range‐dependent waveguides, the phase contribution from mode n is the product of a range‐dependent wave number kn(r) and range. At any given range, kn is dependent on water depth and the depth‐dependent geoacoustic parameters of both the water column and the seabed. To exploit these relationships, inversion algorithms have been developed for estimating range‐dependent seabed properties from the acoustic field measured on synthetic aperture horizontal arrays. These methods are based on inferring information about the waveguide environment by extracting information contained in the phase of the acoustic signal as a function of range. In this talk we examine the individual contributions to the total phase from each of the propagating modes based on changes in depth, sediment sound speed, and water column properties. Sensitivity of individual modes to each of these c...