By Topic

On the use of time-frequency methods in the oceanic passive tomography context

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$33 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

4 Author(s)

A modern method for acoustic underwater channel characterization is the passive tomography concept. The technique relies on the use of opportunity sources thus avoiding the use of dedicated active sources. As a consequence, one of the main difficulties of the concept is due to the lack of any information about the emitted signals. In this paper, we will propose a time-frequency method in the case of linear frequency modulated signals. For an ideal acoustic channel, the received signal is composed of a sum of shifted chirps that have the same chirp rate and start frequency as the emitted signal. Hence, using the fractional Fourier transform (FRFT), it is possible to express the received signal as a sum of sinusoids. Their frequencies are directly related to the time delays of the arrivals. In order to distinguish the closed arrivals, we apply a high resolution spectral estimation method, providing their time delays. Furthermore, we obtain some information related to their amplitudes by comparing the pseudo and the real spectra. These results can further be used in order to estimate the envelope of the impulse response of the acoustic channel.

Published in:

OCEANS 2003. Proceedings  (Volume:2 )

Date of Conference:

22-26 Sept. 2003