Navigation in shallow water using passive acoustic ranging

TL;DR

This paper presents a passive acoustic navigation method for autonomous underwater vehicles in shallow water, utilizing waveguide invariants and single hydrophone measurements to estimate range and position.

Contribution

It introduces a novel passive navigation approach that combines waveguide invariant-based range estimation with a particle filter, enabling accurate AUV positioning using only a single hydrophone.

Findings

Range and range rate can be extracted from pressure fields using waveguide invariants.

The navigation filter bounds position error over time.

Method demonstrated on real and synthetic data.

Abstract

Passive acoustics can provide a variety of capabilities with applications in oceanographic research and maritime situational awareness. In this paper, we develop a method for the navigation of autonomous underwater vehicles (AUVs) in shallow water. Our approach relies on passively recorded signals from acoustic sources of opportunities (SOOs). By making use of the waveguide invariant, a measurement of the range to the SOO is extracted from the spectrogram of a single hydrophone. Range extraction requires knowledge of the range rate, i.e., the radial velocity between the SOO and AUV, computed from the pressure fields at different time intervals. A particle-based navigation filter fuses the range measurements with the AUV's internal velocity and heading measurements. As a result, the position error, which would otherwise increase over time, can be bounded. The ability to compute the range rate and range measurements from the pressure field measured using a single hydrophone is demonstrated on real data from the SWellEx-96 experiment. The capability of the developed navigation filter is shown based on synthetic data generated by the normal mode program KRAKEN.