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Portland State University

Theses/Dissertations

Localization

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Passive Acoustic Vessel Localization, Pasang Sherpa Suwal Jan 2012

Passive Acoustic Vessel Localization, Pasang Sherpa Suwal

Dissertations and Theses

This thesis investigates the development of a low-cost passive acoustic system for localizing moving vessels to monitor areas where human activities such as fishing, snorkeling and poaching are restricted. The system uses several off-the-shelf sensors with unsynchronized clocks where the Time Difference of Arrival (TDOA) or time delay is extracted by cross-correlation of the signal between paired sensors. The cross-correlation function uses phase correlation or Phase Transform (PHAT) which whitens the cross-spectrum in order to de-emphasize dominant frequency components. Using the locations of pairs of sensors as foci, hyperbolic equations can be defined using the time delay between them. With …