Empirical acousto-optic sonar performance versus water surface condition

Abstract

Recent developments in underwater sound detection by laser sensors probing the air-water surface will be presented and discussed. Experimental results will be presented that demonstrate laser sensor performance on detecting underwater sound subject to various water surface conditions. The results will be used for evaluating current laser sensor capabilities and lay the foundation for future hardware design.

Experimental investigation of acousto-optic communications

“…The application of a laser Doppler vibrometer (LDV) to measure in-water acoustic signals by probing an airwater, pressure release surface has been more recently investigated [2][3][4][5][6]. The feasibility tests measured acoustooptic sensitivity values under a range of water surface conditions.…”

“…Laboratory experiments in support of the laser sensor concept demonstrated reception of tonal and digitized biologic, underwater acoustic signals on the airwater interface. An acoustic source level as low as 120 dB//uPa was detected on the air-water boundary and progress has been made in this sensor research for array beamforming for sound source localization and sensor noise analysis [4,5]. Since successful tests were conducted over a range of discrete tonal frequencies (3 to 50 kHz) and frequency bursts (whale communications signals), it is conceivable that the laser sensor is also capable of detecting composite waveforms such as acoustic communication signals at the water surface.…”