SOURCE DEPTH ESTIMATION USING MODAL DECOMPOSITION AND FREQUENCY-WAVENUMBER TRANSFORM

Source localization in shallow water environment is a crucial issue in underwater acoustics. Many methods based on Matched Field Processing (MFP) or on modal decomposi-tion (also called mode filtering) have been developed using a vertical array. The conventional mode filter separates modes using a vertical array of hydrophones. In this case, modes amplitudes are estimated by spatial integration of the pres-sure field which becomes impossible with a horizontal array. In this paper, we propose an efficient method to estimate the source depth by modal decomposition of the pressure field recorded on a horizontal array of hydrophones. Modes amplitudes are estimated using the frequency-wavenumber transform, which is the 2D Fourier transform in time and ra-dial distance. Then predicted modes amplitudes are com-pared to measured modes amplitudes, and source depth is estimated. Robustness against noise of the method is studied and application on real data is presented. 1