Article
Theoretical Model for Correlation Analysis of Wideband Signal Received by Two Vertical Arrays and Retrieval of Modal Dispersion Curves in Shallow Water (en)
* Presenting author
Abstract:
Goal of this work is to model extraction of characteristics of layered bottom (sound speeds in layer and half-space and thickness c(b), c(2), h) using construction of correlation function (matrix) of wideband synthetic sound field radiated by the source. This work`s motivation was experiment carried out by authors in shallow water area. Combination of two vertical line arrays acts as a diffraction grating with 2N hydrophones that uses interference pattern in vertical and horizontal directions and gives more information than one-dimensional array or single receiver. The source is supposed to be moving, like ship, radiating low frequency wideband noise. Our waveguide model constitutes water layer above low sound speed thin layer (c(b)<c. In this waveguide there are two sorts of modes: in dependence on frequency and thickness of sediment’s layer– modes concentrated in water layer and in the bottom layer. It is shown that correlation function constructed in coordinates (phase speed, frequency) allows us to retrieve dispersion curves and to estimate critical frequencies - determining transition between mentioned modes, which in turn give parameters of layered bottom.