Robust source-range estimation using the array/waveguide invariant and a vertical array.

The array invariant based on beam-time migration has been proposed for source-range estimation using a horizontal or vertical array (VA), with no need for forward model computations. The approach has been demonstrated successfully with experimental data in shallow water using a horizontal towed array. Recently, the array invariant has been shown to be a special case of the waveguide invariant theory. In this paper, the unified array/waveguide invariant approach to source-range estimation is applied to a short-aperture VA in a fluctuating ocean environment over a one-day period. Specifically, the mean range estimates using a 12-m long VA in ∼100 m deep water are <8% relative error for a source (2-3 kHz) at 6-km range, demonstrating the robustness of this approach.