A Vector Sensor-Based Acoustic Characterization System for Marine Renewable Energy

Abstract

NoiseSpotter is a passive acoustic monitoring system that characterizes, classifies, and geo-locates anthropogenic and natural sounds in near real time. It was developed with the primary goal of supporting the evaluation of potential acoustic effects of offshore renewable energy projects. The system consists of a compact array of three acoustic vector sensors, which measures acoustic pressure and the three-dimensional particle velocity vector associated with the propagation of an acoustic wave, thereby inherently providing bearing information to an underwater source of sound. By utilizing an array of three vector sensors, the application of beamforming techniques can provide sound source localization, allowing for characterization of the acoustic signature of specific underwater acoustic sources. Here, performance characteristics of the system are presented, using data from controlled acoustic transmissions in a quiet environment and ambient noise measurements in an energetic tidal channel in the presence of non-acoustic flow noise. Data quality is demonstrated by the ability to reduce non-acoustic flow noise contamination, while system utility is shown by the ability to characterize and localize sources of sound in the underwater environment.

Analysis and Experimental Verification of Model Solutions of the Pekeris Boundary Problem in the Infrasonic Frequency Range

“…Receiving systems based on combined receivers (CR) are widely used in the study of sound fields generated by natural or simulated sources. An example is the work [10][11][12][13][14][15], in which extensive experimental studies of the main characteristics of sound fields with the use of combined receivers were carried out. In this work, the emphasis of experimental studies is placed on the comparison of experimental data and various model descriptions of the sound field in the Pekeris waveguide, which are listed above.…”

Clearing a Path to Commercialization of Marine Renewable Energy Technologies Through Public–Private Collaboration

“…NoiseSpotter R NoiseSpotter R is a passive acoustic monitoring device developed by Integral Consulting Inc. (Integral) to characterize, classify, and provide accurate location information, in near real-time, for underwater anthropogenic and natural sounds (Raghukumar et al, 2020). It consists of a compact array of particle motion sensors that measure acoustic pressure and three-dimensional particle velocities associated with the propagation of an acoustic wave, enabling triangulation of individual bearings and sound source localization with a single unit (Raghukumar et al, 2020). These sensors (GeoSpectrum Technologies Inc.) measure triaxial particle motion and omnidirectional pressure at a frequency range of 50 Hz -3 kHz, at a sample rate of 20 kHz, as well as earth-referenced orientation with an integrated inertial measurement unit (IMU).…”

“…The remaining issues for the NoiseSpotter R V3 design included mitigating potential acoustic reflectance from aluminum, time-consuming system mobilization, and insufficient power. NoiseSpotter R V4a,b (TRL 7, 8) was thus redesigned with modular, high-density polyethylene frames (Figure 2D; Raghukumar et al, 2020) to reduce acoustic reflectance potential and custom 258 Ahr rechargeable battery packs. NoiseSpotter R V4b includes onboard realtime data processing and telemetry of acoustic data metrics to a cloud server.…”

Spectral-Correlation Signal Processing in the Infrasonic Frequency Range

“…In recent years, there has been a tendency of increasing interest in such systems [1][2][3][4][5][6][7]. Extensive studies of sound fields using combined receivers are given in [8][9][10][11][12][13][14]. The potential capabilities of a single CR are characterized by its noise immunity [15], which is the most important characteristic of the combined receiver.…”