Wavenumber spectrum estimation for geoacoustic inversion using Hankel transform based on passive synthetic aperture method

A geoacoustic inversion of sediment parameters based on passive synthetic aperture for a moving autonomous underwater vehicle (AUV) and a source emitting continuous tone signal is proposed in this paper. An accurate representation of a received signal on moving receiver in the time domain is derived for the Doppler-shifted field. The depth-dependent Green's function is obtained by performing a Hankel transformation on the pressure field. Geoacoustic parameters are determined using a grid search scheme for the ambiguity function, which is constructed by the Bartlett matched processor. The restricted physical aperture of a flank array or towed array on AUV is extended to a large synthetic aperture. The purpose is to improve the resolution of the wavenumber spectrum. The simulations have shown that the results of geoacoustic inversion are closer to the real value as the AUV motion distance increases.