Modal characteristic frequency in a range-dependent shallow-water waveguide and its application to passive source range estimation

In order to implement robust passive source ranging in a range-dependent shallow-water waveguide, the modal characteristic frequencies are theoretically analyzed based on warping transform. Formulae of the modal spatiotemporal arrival structure and instantaneous phase are derived in the waveguide with an absolute hard bottom. The relationship between the characteristic frequency and the source-receiver range is developed. With the relationship, a modified passive source-range estimation approach is presented in a range-dependent shallow-water waveguide. Simulation and experiment verify the theory and the approach.