| Inferring Bottom Acoustic Properties from AN/SQQ-32 Sonar Reverberation Data in Order to Reduce False Targets in Bottom/Buried Mine Detection |
APR 2002 |
11 pages |
| Authors:
Henry H. Howell; Robert H. Bourke; James H. Wilson; J. M. Null and; Josette Fabre; FLEET NUMERICAL OCEANOGRAPHIC CENTER MONTEREY CA
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 | Bottom/sub bottom geoacoustic properties must be determined to high spatial resolution in order to reduce false targets for bottom/buried mine detection. Inversion techniques (ITs) are used to infer bottom geoacoustic properties using AN/SQQ-32 beam reverberation level (RL) time series data acquired in Rhode Island Sound in February 1993. A technique was developed wherein the deviation of the RL for an individual ping and beam from an area-wide average RL is ... |
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| Method and Apparatus for Reducing Noise from Near Ocean Surface Sources |
01 OCT 2001 |
22 pages |
| Authors:
James B. Donald; James H. Wilson; DEPARTMENT OF THE NAVY WASHINGTON DC
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| The present invent ion is directed to a method and system for significantly reducing the acoustic noise from near-surface sources using an array processing technique that utilizes Multiple Signal Classification (MUSIC) beamforming and the Lloyd's Mirror interference pattern at very low frequencies. Noise from nearby near-surface sources, such as merchant ships, super tankers, fishing trawlers, seismic profiling platforms, or other sources near the ocean surface can significantly interfere with the ... |
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| Development of an Arctic Low Frequency Ambient Noise Model |
30 SEP 1998 |
4 pages |
| Authors:
Robert H. Bourke; James H. Wilson; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF OCEANOGRAPHY
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| Our long-term goal is to develop a low frequency ambient noise model capable of predicting extreme (loud/quiet) noise events in Arctic ice-covered waters due to the presence or absence of storms. We wish to determine the internal stress of the ice canopy covering the Arctic ocean due to convergent atmospheric forcing and relate this to energy dissipation rate due to ridge building, the major source of ambient noise in the ... |
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| Tracking System and Method. |
JAN 1996 |
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| Authors:
James B. Donald; Albert H. Nuttail; James H. Wilson; DEPARTMENT OF THE NAVY WASHINGTON DC
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 | A method and apparatus for detecting, processing and tracking sonar signals to provide bearing, range and depth information that locates an object in three dimensional underwater space. An inverse beamformer utilizes signals from a towed horizontal array of hydrophones to estimate a bearing to a possible object. A matched field processor receives measured covariance matrix data based upon signals from the hydrophones and signals from a propagation model. An eight ... |
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| Inverse Beamforming Sonar System and Method. |
01 JUN 1993 |
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| Authors:
James Donald; Albert H. Nuttail; James H. Wilson; DEPARTMENT OF THE NAVY WASHINGTON DC
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| An apparatus and method for detecting, processing, and tracking sonar signals is provided. Plane wave energy from the sonar signal source is measured at multiple points using an array of plane wave energy receptors. These measurements are processed using an inverse beamformer to generate output beam levels. These output beam levels are then processed using the spectrum normalizer to yield spatially and spectrally normalized output beam levels. The normalized beam ... |
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