Possibility of acoustic noise interferometry applications for passive remote sensing in shallow water

Abstract

The cross-coherence function of the ambient noise field received during the quite long accumulation time by two hydrophones in the shallow water can exhibit two peaks. These peaks correspond to the travel times of signals between these two hydrophones. If the features of the shallow water are changed than the positions of these peaks are shifted. As result one can get information to reconstruct the physical properties and variability of the underwater environment using such peaks’ shifts. In this work, the possibility of the passive remote sensing in shallow water features is considered based on the time-frequency analysis of the ambient noise cross-coherence function. The key point which define the possibilities of this method are the accumulation times required to estimate the peaks of the noise cross-coherence function with the acceptable signal-to-noise ratio. It is shown that the desired accumulation times can be considerably reduced by the appropriate choice of the frequency bands where the noise fields are formed by the small number of the incoherent hydroacoustic modes.