Principle Investigator Contact Information
Phone: 858 752 0705
This project develops an array of sensors that measures sound and locates sound sources in near real time. The array, called the “NoiseSpotter,” is intended to evaluate environmental effects of marine renewable energy (MRE) installations. This system will distinguish MRE device noise from surrounding sounds, including flow noise, and relay noise metrics (e.g., sound levels, signal-to-noise ratios, sound source location, etc.) in near real time to a land-based observer using a cellular or satellite telemetry link.
Department of Energy, Energy Efficiency and Renewable Energy
Location of Research
Santa Cruz, California
To develop a new, autonomous, real-time, low-cost, ocean acoustic monitoring system (NoiseSpotter) by integrating an array of acoustic pressure and particle velocity sensors (vector sensors) with a surface buoy equipped with near real-time communication technology. Integration of direct particle velocity measurements (in addition to acoustic pressure measurements) will provide better identification of MHK device noise, sound source localization, and allow for assessment of potential environment effects of acoustic particle velocity on marine mammals and fish.
Currently in the last year of a 3 year project. Sensors have been integrated, location estimation algorithm and flow noise removal mechanisms have been developed, and the real-time telemetry of analysed data has been demonstrated. The team is currently awaiting permitting decisions for a final demonstration at the Wave Energy Test Site in Oahu, Hawaii.
The NoiseSpotter has been demonstrated to be an easily deployable self-logging vector sensor array. The results of field trials from a variety of environments show excellent data quality in each of these environments with regard to discerning controlled source transmissions and sources of opportunity. The ability to mitigate flow noise, key in energetic environments, was demonstrated in a tidal channel with approximately 9 dB reduction of flow noise at 200 Hz. The in-water tests indicate that the hardware configuration is suitable for small-vessel (~8-m vessel length) operations in quiescent and energetic environments.
The ability of the NoiseSpotter to estimate the location of a source of sound has been demonstrated using plane-wave beamforming techniques applied to a vector sensor array. The compact size of the vector sensor array allows for beamforming array gain comparable to much larger hydrophone arrays. Location estimates of the controlled source were found to be within 2% of the source-receiver separation.
Kaustubha Raghukumar, Frank Spada, Grace Chang, Craig Jones. Initial field trials of the NoiseSpotter: an acoustic monitoring and localization system. Marine Energy Technology Symposium, Washington D.C. 2018.