Warping fréquentiel pour l'estimation du temps d'arrivée des modes en acoustiques sous-marines
Résumé
Shallow water is a classical environment for underwater acoustics. However, it is still a challenging one when coupled with broadband low-frequency source and single receiver configuration. Indeed in this case, the received signal is formed by several modes. These modes are overlapped in time and in frequency, and their time frequency pattern has curved features. This paper presents a frequency warping method (applied on the spectrum of the received signal) which transforms a given mode into a Dirac (in time domain).The warped signal can then be represented with classical tools. The frequency warping allows an estimation of modal arrival times, and can be used as a preprocessing when signal detection is required. It is succefully applied on real data.
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