Transient localization in shallow water environments
By: Joachim Brune
Publisher: Naval Postgraduate School; Available from National Technical Information Service
Published: 1998
Place of publication: Monterey, Calif; Springfield, Va
Language: eng
Number of pages: 76
Description: In this work, the robustness of a simple, Bartlett-type processor based on matching broadband signal      autocorrelation functions is investigated. Measures of robustness to be examined include the size of the      localization footprint on the ambiguity surface and the peak-to-sidelobe levels in the presence of      environmental mismatch and noise. A full-wave PE model is used to produce broadband replicas. Both      model-generated synthetic signals, which provide baseline results, and measured pulses in a shallow water      environment are analyzed. This work suggests that environmental mismatch has a more significant effect on      the localization performance than noise. It also suggests that, as long as the noise level is not higher than      the signal level, the localization performance will not be significantly affected. This is to be expected, since      for white noise the majority of the influence on the autocorrelation function occurs at zero lag which has      been removed in the localization algorithms. It is also shown that the autocorrelation matching in the      time-domain is generally more useful for smaller bandwidths at low frequencies, which has been observed      in previous work, whereas the autocorrelation matching in the frequency-domain is better suited for larger      bandwidths and higher frequencies.
Notes: "March 1998."

Thesis advisor(s): Kevin B. Smith, Ching-Sang Chiu, Ralph Hippenstiel.

Thesis (M.S. in Electrical Engineering and Engineering Acoustics) Naval Postgraduate School, March 1998.

Includes bibliographical references (p. 71-73).

"Approved for public release, distribution unlimited"--Cover.

Also available online.

Mode of access: World Wide Web.

System requirements: Adobe Acrobat reader.

German Navy author.

dk/dk cc:9116 6/25/98.