Source depth estimation using matched field processing and frequency-wavenumber transform

Matched field processing (MFP) is frequently used to localize underwater sources, in range and depth, using vertical arrays recording ultra low frequency waves (/spl les/100Hz). In this paper, we use matched-field techniques, guided waves propagation and signal processing tools to estimate source depth in a shallow water environment with a horizontal array. MFP is performed in the frequency-wavenumber domain: frequency-wavenumber transform (f-k) is the square modulus of the 2D Fourier transform in time and radial distance. This f-k representation provides much information on guided propagation of Ultra Low Frequency waves in shallow water: on this representation, modes can be separate. Besides, modes excitation depends on the source depth. As a result, it is possible to estimate the source depth using MFP based on modes excitation factors.