Doppler processing of phase encoded underwater acoustic signals
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Authors
Eldred, Randy Michael
Subjects
Acoustic tomography
Fast Hadamard Transform
maximal-length sequences
Doppler processing
Fast Hadamard Transform
maximal-length sequences
Doppler processing
Advisors
Miller, James H.
Date of Issue
1990-09
Date
1990-09
Publisher
Monterey, California: Naval Postgraduate School
Language
Abstract
Travel time of an acoustic signal from transmitter to receiver provides a great deal of information about the ocean environment. Variations in the travel time of the signal may be caused by the changes in the sound speed along the path. Since sound speed is a function of pressure, temperature and salinity, measurement of this parameter in acoustic tomography provides a means to observe ocean fluctuations through the use of inverse techniques. The upcoming Heard Island Experiment will attempt to determine the feasibility of measuring global warming by measuring changes in signal travel time that may be caused by temperature changes in the world's oceans. The signals to be transmitted in this experiment are phase encoded maximal-length sequences of various lengths which are well suited to measurement of travel time. The objectives of this thesis are to provide a software package, in C, that will allow participation as a receiver in this experiment, and to provide a general capability to process any maximal-length sequence, transmitted at any carrier frequency and with any reasonable Doppler. A background on wave propagation, maximal-length sequences, and Doppler processing are presented in this thesis.
Type
Thesis
Description
Series/Report No
Department
Electrical Engineering
Organization
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
Sponsors
Funder
Format
viii, 99 p. ill.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.