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

Abstract

The array invariant based on beam-time migration has been proposed for instantaneous source-range estimation in acoustic waveguides using a horizontal or vertical array. With minimal knowledge of the environment, the approach has been demonstrated successfully with experimental data in shallow water using a horizontal array. Moreover, it was determined recently that the array invariant can be derived from waveguide invariant theory based on the dependence of group speed on phase speed. In this paper, the array/waveguide invariant approach to source-range estimation is applied to a vertical array in a fluctuating ocean environment over a one-day period. Specifically, the range estimates using a 12-m long vertical array in ∼100 m deep water are within 9–16% relative error for a 2–3 kHz source at 6-km range, demonstrating the robustness of this approach.