Enhancing instantaneous wide-area ocean acoustic sensing and directional soundscaping with large aperture coherent hydrophone arrays
Abstract
Approved for Public ReleaseThe goal of this research is to enhance our understanding of underwater sound and its applicationto instantaneous wide-area acoustic sensing in the undersea environment. We will examine andcharacterize sound radiated from natural and man-made sources to infer and understandmechanisms for sound production or generation in the ocean. We will quantify underwatersound pressure levels and associated statistics for measured narrowband and broadband sourcesin bounded and unbounded ocean media, and apply this analysis to further develop and enhancestatistical-physics based models for the moments of underwater sound pressure fields and levelsin order to improve understanding of undersea sound propagation and fluctuation. These resultsand findings will be applied to guide development of array and signal processing algorithms toimprove efficacy of long-range and instantaneous wide-area underwater sensing in primarilypassive and some active sensing applications. Instantaneous wide area sensing is accomplishedusing large aperture coherent hydrophone arrays. Coherent array processing or beamforming ofboth uniform and nested non-uniform array subapertures will be applied to measured hydrophonearray data to enhance signal-to-noise ratio, determine directional dependence of underwatersound, and provide directional soundscape levels. Furthermore, bearing-time measurements ofrepetitive acoustic signals received from an undersea object will be analyzed to infer its locationwith associated error bounds in localization estimation. These results will beutilized to generate2D wide-area soundscape imagery of the undersea environment including its evolution overtime. This auditory scene analysis will provide valuable insights into ocean entities present in agiven environment, their temporo-spatial distributions and elucidate relationships includingdependence on features of the undersea environment. The research objectives will be developed,tested and accomplishedvia analysis of coherent hydrophone array data from previous seaexperiments acquired with the ONR-FORA array, including the Gulf of Maine 2006 and theNordic Seas 2014 Experiments, as well as current and future sea experiments acquired using theinhouse-developed Northeastern University (NU) 160-element coherent hydrophone array, suchas the most recent US Northeast coast 2021Experiment with both shallow water and deep oceanacoustic observations. We will investigate approaches for co-registration and fusion of wideareapassive acoustic sensing results with other sensing modalities, such as wide-area activeacoustic imaging and local ultrasonic echosounding, including inputs from air-borne andunderwater optical camera imagery for visual identification and confirmation.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 12, 2023
- Source ID
- N000142312327
Entities
People
- Purnima Makris
Organizations
- Northeastern University
- Office of Naval Research
- United States Navy