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). / 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. / by Theodore Herbert Schroeder. / S.M.
| Identifer | oai:union.ndltd.org:MIT/oai:dspace.mit.edu:1721.1/29063 |
| Date | January 2002 |
| Creators | Schroeder, Theodore Herbert, 1967- |
| Contributors | James F. Lynch., Woods Hole Oceanographic Institution., Massachusetts Institute of Technology. Dept. of Ocean Engineering., Joint Program in Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution., Massachusetts Institute of Technology. Department of Ocean Engineering |
| Publisher | Massachusetts Institute of Technology |
| Source Sets | M.I.T. Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 105 p., 7152011 bytes, 7151768 bytes, application/pdf, application/pdf, application/pdf |
| Rights | M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission., http://dspace.mit.edu/handle/1721.1/7582 |
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