Underwater acoustic communication experimentation: The acoustic communications and data storage (ACDS) system

Abstract

The Naval Research laboratory has developed a sea-going system, currently consisting of three acoustic communications and data storage (ACDS) buoys. The buoys can be deployed in the water column, moored to the ocean floor, or towed behind a ship to emulate an autonomous underwater vehicle (AUV). The system is intended for semi-real-time acoustic communications in situ and continuous recording of the raw acoustic data in the water for postexperiment analysis. The purpose is to study environmental issues affecting high data rate point-to-point acoustic communications as well as multiple-in-multiple-out acoustic networking. Each ACDS has an acoustic projector and an array of eight hydrophones. It is designed for two frequency bands: 2–5 kHz and 15–25 kHz. The system has been deployed in several oceans. Modulation signals used include binary and quadrature phase-shifted keying (BPSK/QPSK), frequency-hopped frequency-shifted keying (FH FSK), orthogonal frequency division multiplexing (OFDM) and code division multiple access (CDMA) signals. The acoustic modem is based on the Acoustic Modem Software developed by WHOI and improved by the Naval Underwater Warfare Center, Newport, RI. Acoustic networking signals are used to aid vehicle navigation. [Work supported by ONR.]

Phase Shift Keying Acoustic Communication in Air with Impulse Response

“…Recently, there has been an increase in the amount of research on acoustic communication, particularly in an underwater environment, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] because radio communication underwater is challenging owing to the rapid attenuation of electromagnetic waves. In contrast, acoustic communication in air is not often used because acoustic waves attenuate rapidly therein.…”