Vector Hydrophone Passive Time Reversal for Underwater Acoustic Communications

The use of vector hydrophones as a receiver for underwater communications has been the subject of research since such device is a compact option to pressure-only arrays. A vector hydrophone, usually called acoustic vector sensor, is a device that measures pressure and particle velocity components. This paper investigates a method to combine those channels based on passive time-reversal (PTR). Simulation and experimental data are used to quantify communication performance, comparing vector hydrophones to pressure-only arrays. The analyzed acoustic scenario consists of a shallow-water area (about 100 m), where a vector hydrophone array receives communication signals from a bottom moored source. Simulations help in the understanding of diversity by analyzing spectral characteristics of vector hydrophone channels and the PTR q-function. While in simulation, the benefits of PTR using particle velocity channels are perceptible seen by exploring diversity, communication performance with experimental data is degraded due to time-varying. Finally, the achieved performance using a single or a small array of vector hydrophones enforces its benefits for communication enhancement.