Abstract:
Low frequency acoustic propagation in shallow water is examined from a normal
mode context. By modelling the far field pressure field as a modal sum, propagating mode
characteristics of wavenumber, initial phase, attennation and amplitude may be estimated
using a high resolution parameter modeling technique. The advantages of such an
algorithm are the resolution of closely spaced modes in a range independent environment
and the ability to analyze range dependent waveguides.
This thesis presents the application of a Prony algorithm to the shallow water
environment. The algorithm operates directly on the signal matrix. Synthetically
generated, range independent pressure fields are used to analyze the technique'S
performance and to observe its sensitivity to variations in model specifications. Noise is
added to determine the threshold of acceptable performance. As a consequence of field data
tests, further enhancements to the algorithm are suggested.
Range dependent performance is evaluated on a coastal wedge example and
geoacoustic parameter shift example.
