Horizontal linear array sensor localization and preliminary coherence measurements from the 2001 ASIAEX South China Sea experiment
Name
51758115-MIT.pdf
Description
Full printable version
Size
9.43 MB
Format
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Checksum (MD5)
08d3d505721160edcaf7a8b55bc0fc35
Author(s)
Schroeder, Theodore Herbert, 1967-
Advisor(s)
James F. Lynch.
Alternative Title
Horizontal linear array sensor localization and preliminary coherence measurements from the 2001 Asian Seas International Acoustic Experiment SCS experiment
Date Issued
2002
Publisher
Massachusetts Institute of Technology
Abstract
This thesis examines data collected in the South China Sea (SCS) component of the 2001 Asian Seas International Acoustic Experiment (ASIAEX), where a fixed Horizontal Linear Array (HLA) was deployed to study transverse array coherence in a coastal environment. Arrays obtain their gain and directivity by coherently adding the energy that impinges on them. Therefore, to maximize the efficiency of an array, the size of the aperture over which the signal remains coherent needs to be determined. Scattering of sound by the ocean environment, especially in coastal areas, reduces the coherence of acoustic signals, and thereby limits the useful aperture of an acoustic array. During ASIAEX, a horizontal linear array was deployed on the continental shelf of the South China Sea in order to directly measure the acoustic coherence in a coastal environment. 224 Hz and 400 Hz sources were placed on the continental slope to provide an up slope propagation path and a 400 Hz source was placed on the shelf to provide an along shelf propagation path. This thesis analyzes one day of transmissions from these three sources and gives the first look at coherence lengths of the HLA determined by sensor-to-sensor correlations. To achieve this, the thesis analyzes continuous time series data from the Long Base Line (LBL) navigation system and two days of light bulb drops to provide array sensor localization. Accurate sensor positions are needed to determine the correlation versus sensor separation distance and ultimately the array coherence length.
Description
Thesis (S.M.)--Joint Program in Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Ocean Engineering and the Woods Hole Oceanographic Institution), 2002.
Includes bibliographical references (p. 105).
Subjects
Ocean Engineering.
/Woods Hole Oceanographic Institution. Joint Program in Applied Ocean Science and Engineering.
Woods Hole Oceanographic Institution.
MIT Department
Joint Program in Applied Ocean Physics and Engineering
Woods Hole Oceanographic Institution
Massachusetts Institute of Technology. Department of Ocean Engineering
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