Vertical Directionality of Low-Frequency Wind Noise and Vertical Array Optimization for the Wind Noise Limit

Normal mode-based noise modeling is applied to investigate the structure and the environment dependence of vertical wind noise directionality and the optimal design of vertical arrays for detection in a wind noise background, using, as examples, two deep-water sites, one in the North Atlantic and th...

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Bibliographic Details
Main Authors: Hayward, Thomas J., Heitmeyer, Richard M.
Other Authors: NAVAL RESEARCH LAB WASHINGTON DC
Format: Text
Language:English
Published: 2004
Subjects:
Acoustic Detection and Detectors
Acoustics
*ACOUSTIC ARRAYS
*ACOUSTIC VELOCITY
*SEDIMENTS
*BACKGROUND NOISE
POWER LEVELS
ANNEALING
OPTIMIZATION
ENVIRONMENTS
DETECTION
OCEAN SURFACE
DISTRIBUTION
SIGNAL TO NOISE RATIO
SURFACE ROUGHNESS
VERTICAL ORIENTATION
LIMITATIONS
ATTENUATION
MEAN
BEAMS(RADIATION)
DEEP WATER
LOW FREQUENCY
SIDELOBES
ACOUSTIC FIELDS
NORTH PACIFIC OCEAN
DIRECTIONAL
PE62435N
6701
Pacific
North Atlantic
Online Access:http://www.dtic.mil/docs/citations/ADA426191
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA426191
Description
Summary:Normal mode-based noise modeling is applied to investigate the structure and the environment dependence of vertical wind noise directionality and the optimal design of vertical arrays for detection in a wind noise background, using, as examples, two deep-water sites, one in the North Atlantic and the other in the North Pacific. The contributions to the noise directionality of the overhead (direct-path), surface-interacting, and sediment-interacting components of the noise field are examined through analysis of the vertical noise response of a reference aperture. Environmental influences investigated include the effects of (1) the wind noise source distribution in range, and (2) the acoustic propagation environment, including water-column depth and sound speed, sediment attenuation, and sea surface roughness. Spatial configurations of vertical arrays with arbitrary phone spacing are optimized by simulated annealing to maximize a measure of the mean array The beam patterns of the optimized arrays adapt to the noise directionality by trading off beamwidth, sidelobe levels, and single-element signal-to-noise ratio. The original document contains color images.

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