Acoustic Clutter and Ocean Acoustic Waveguide Remote Sensing (OAWRS) in Continental Shelf Environments

2008 ◽  
Author(s):  
Nicholas C. Makris
Keyword(s):  
Remote Sensing ◽  
Continental Shelf ◽  
Acoustic Waveguide

Detection, localization, and classification of multiple ocean vehicles over continental-shelf regions with passive ocean acoustic waveguide remote sensing

2017 ◽  
Vol 142 (4) ◽  
pp. 2495-2495
Author(s):  
Chenyang Zhu ◽  
Nada Saghir ◽  
Haoqing Li ◽  
WEI HUANG ◽  
Olav Rune Godø ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Continental Shelf ◽  
Acoustic Waveguide

scholarly journals Detection, Localization and Classification of Multiple Mechanized Ocean Vessels over Continental-Shelf Scale Regions with Passive Ocean Acoustic Waveguide Remote Sensing

2018 ◽  
Vol 10 (11) ◽  
pp. 1699 ◽  
Author(s):  
Chenyang Zhu ◽  
Heriberto Garcia ◽  
Anna Kaplan ◽  
Matthew Schinault ◽  
Nils Handegard ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Continental Shelf ◽  
Signal To Noise Ratio ◽  
Automatic Identification ◽  
Identification System ◽  
Underwater Sound ◽  
Constant Frequency ◽  
Acoustic Waveguide ◽  
Time Frequency ◽  
Hydrophone Array

Multiple mechanized ocean vessels, including both surface ships and submerged vehicles, can be simultaneously monitored over instantaneous continental-shelf scale regions >10,000 km 2 via passive ocean acoustic waveguide remote sensing. A large-aperture densely-sampled coherent hydrophone array system is employed in the Norwegian Sea in Spring 2014 to provide directional sensing in 360 degree horizontal azimuth and to significantly enhance the signal-to-noise ratio (SNR) of ship-radiated underwater sound, which improves ship detection ranges by roughly two orders of magnitude over that of a single hydrophone. Here, 30 mechanized ocean vessels spanning ranges from nearby to over 150 km from the coherent hydrophone array, are detected, localized and classified. The vessels are comprised of 20 identified commercial ships and 10 unidentified vehicles present in 8 h/day of Passive Ocean Acoustic Waveguide Remote Sensing (POAWRS) observation for two days. The underwater sounds from each of these ocean vessels received by the coherent hydrophone array are dominated by narrowband signals that are either constant frequency tonals or have frequencies that waver or oscillate slightly in time. The estimated bearing-time trajectory of a sequence of detections obtained from coherent beamforming are employed to determine the horizontal location of each vessel using the Moving Array Triangulation (MAT) technique. For commercial ships present in the region, the estimated horizontal positions obtained from passive acoustic sensing are verified by Global Positioning System (GPS) measurements of the ship locations found in a historical Automatic Identification System (AIS) database. We provide time-frequency characterizations of the underwater sounds radiated from the commercial ships and the unidentified vessels. The time-frequency features along with the bearing-time trajectory of the detected signals are applied to simultaneously track and distinguish these vessels.

scholarly journals The Effect of Attenuation from Fish on Passive Detection of Sound Sources in Ocean Waveguide Environments

2021 ◽  
Vol 13 (21) ◽  
pp. 4369
Author(s):  
Daniel Duane ◽  
Chenyang Zhu ◽  
Felix Piavsky ◽  
Olav Rune Godø ◽  
Nicholas C. Makris
Keyword(s):  
Remote Sensing ◽  
Propagation Path ◽  
Experimental Measurements ◽  
Sound Sources ◽  
Detection Range ◽  
Acoustic Waveguide ◽  
Passive Sensing ◽  
Surface Vessels ◽  
Theoretical Predictions ◽  
Radiated Sound

Attenuation from fish can reduce the intensity of acoustic signals and significantly decrease detection range for long-range passive sensing of manmade vehicles, geophysical phenomena, and vocalizing marine life. The effect of attenuation from herring shoals on the Passive Ocean Acoustic Waveguide Remote Sensing (POAWRS) of surface vessels is investigated here, where concurrent wide-area active Ocean Acoustic Waveguide Remote Sensing (OAWRS) is used to confirm that herring shoals occluding the propagation path are responsible for measured reductions in ship radiated sound and corresponding detection losses. Reductions in the intensity of ship-radiated sound are predicted using a formulation for acoustic attenuation through inhomogeneities in an ocean waveguide that has been previously shown to be consistent with experimental measurements of attenuation from fish in active OAWRS transmissions. The predictions of the waveguide attenuation formulation are in agreement with measured reductions from attenuation, where the position, size, and population density of the fish groups are characterized using OAWRS imagery as well as in situ echosounder measurements of the specific shoals occluding the propagation path. Experimental measurements of attenuation presented here confirm previous theoretical predictions that common heuristic formulations employing free space scattering assumptions can be in significant error. Waveguide scattering and propagation theory is found to be necessary for accurate predictions.

scholarly journals Designing ocean acoustic waveguide remote sensing for target detecting and tracking

2018 ◽  
Vol 1075 ◽  
pp. 012058
Author(s):  
H M Manik ◽  
Susilohadi ◽  
B R Kusumah ◽  
A Dwinovantyo ◽  
S Solikin
Keyword(s):  
Remote Sensing ◽  
Acoustic Waveguide ◽  
Target Detecting
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