Depth-tracking of a near-surface target from the deep ocean

Abstract

Determining the depth of an acoustic source in a deep ocean environment can be approached using a variety of existing methods, each with inherent limitations. A method for determining the depth of a moving near-surface acoustic target from a fixed vertical array below the deep ocean critical depth is presented using the characteristics of the Lloyd mirror pattern of a near-surface acoustic signal and a library of calculated patterns. Depth estimates of the moving target are made in real-time and incorporated into a confidence metric for tracking the target motion. Results indicate that this method is robust, performing well in conditions involving environmental mismatch and a moderate amount of surface noise.