Horizontal linear array sensor localization and preliminary coherence measurements from the 2001 ASIAEX South China Sea experiment / by Theodore Herbert Schroeder.
Schroeder, Theodore Herbert.
MetadataShow full item record
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.
Showing items related by title, author, creator and subject.
Wolf, Rebecca E. (Monterey, California. Naval Postgraduate School, 2007-06);In August of 2006 the Adaptive Sampling and Prediction (ASAP) experiment was conducted near the northern Monterey Bay. Multiple assets including aircraft, autonomous vehicles, moorings, and numerical models were used to ...
Experimental and theoretical performance of a particle velocity vector sensor in a hybrid acoustic beamformer Caulk, Jeffrey V. (Monterey, California: Naval Postgraduate School, 2009-12);Acoustic measurements have traditionally relied exclusively on sound pressure sensors. This research investigated the performance of Microflown 3D hybrid pressure and acoustic particle velocity sensors in a linear array. ...
Chiu, Ching-Sang (2008-09);My long-term research goals are: (1) The characterization, understanding, and prediction of the statistics (mean, variance and coherence) of low-frequency acoustic signals and ambient noise in the littoral zone. The signal ...