Time-Frequency Features of 3-D Sound Propagation in Wedge-Shaped Oceanic Waveguides
Résumé
This paper considers propagation of low-frequency
broadband pulses in shallow water. It focuses on across-slope
propagation in wedge-shaped oceanic waveguides and on
single hydrophone receiving configurations. In a low-frequency
shallow-water context, propagation is dispersive and usually
described by modal theory. However, in the presence of a tilted
bottom, propagation is also affected by 3-D effects (horizontal
refractions). The paper shows that time-frequency analysis is
a suitable tool to illustrate and understand 3-D propagation. It
illustrates the pertinence of the time-frequency analysis of 3-D
signal by proposing an algorithm to estimate the seabed slope
using a single receiver. The method is benchmarked on numerical
simulations, and successfully applied on small-scale experimental
data.