Mode Selection in Oceanic Waveguides

A method is proposed for selecting modes and estimating their parameters in shallow water using a single receiver. The method is based on the two-dimensional time–frequency Fourier transform of the moving-source field. The spectral density given by the integral transform is concentrated in the form of focal spots, corresponding to individual modes. A relationship of the mode phase and group velocities with the coordinates of focal-spot peaks is established. Filtering of focal spots and application of the two-dimensional inverse Fourier transform to them reconstructs the fields of selected modes. The results of numerical simulation are presented. The reconstructed modal parameters (amplitude, real part of horizontal wave number, group velocity, damping coefficient) are estimated.