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Type of Document Master's Thesis
Author Aluko, Obadamilola
URN etd-04132004-132153
Title Implementation and Application of dispersion-based waveguide models for shallow-water sonar processing
Degree Master of Science in Electrical Engineering
Program Electrical Engineering
School School of Engineering
Advisory Committee
Advisor Name Title
Patrick Loughlin Committee Chair
Amro A. El-Jaroudi Committee Member
Luis F. Chaparro Committee Member
Keywords
  • ocean acoustics
  • FIR filter
  • sound in water
  • group velocity
  • 2-plate wavegude
  • pekeris waveguide
  • waveguide
  • dispersion
Date of Defense 2003-12-04
Availability restricted
Abstract
In wave propagation, the phenomenon of dispersion, whereby different frequencies travel at different velocities, can result in significant nonstationarities, i.e., time- and spatially-varying characteristics of the wave. This effect is particularly strong in shallow water sound propagation, due to the waveguide-like action of the ocean bottom and surface.

These channel-induced nonstationarities can have a deleterious impact on automatic detection and classification in the absence of signal processing techniques that account for dispersive channel effects.

We quantify the effects of dispersion on the spatial and temporal spreading of a propagating wave by considering local temporal, spatial and spectral moments of the modes of the wave. By local moments we mean, for example, the spread (standard deviation) of the wave in time at a particular location; or the average frequency of the wave at a particular time. We implement simple dispersion-based waveguide models of a shallow ocean channel and demonstrate by application to impulsive-source sonar data that

simple channel models requiring little environmental information can be used to compensate for the effects of dispersion.

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