Spatio-Temporal Characterization of the Underwater Acoustic Propagation: Group and Phase Velocities Reconstruction
Caractérisation Spatio-Temporelle de la Propagation Acoustique Sous-Marine: Reconstruction des Vitesses De Groupeet de Phase
OPEN ACCESS
This study deals with the inverse problem in Ocean Acoustic Tomography by using the modal theory. We consider a range independent environment and a large vertical array receiver . We show inthe case of the homogeneous medium First and in the general case then, that the beamforming patterns allow to reconstruct the link between the horizontal group velocities and the phase velocities of the propagated waves. Finally, we consider two applications : the direct sound speed reconstruction without a priori information and the depth estimation of transmitters or receivers.
Résumé
Cette étude traite du problème inverseen Tomographie Acoustique Océanique par la théorie des modes . Nous considérons des milieux de propagation invariants en distance. A partir des signaux reçus sur une antenne verticale, nous montrons d'abord dans le cas particulier du guide d'ondes homogène, puis dans le cas général, qu'un traitement classique par formation de voies permet de reconstituer le lien entre les vitesses de groupe horizontales et les vitesses de phase des ondes propagées dans le milieu. Nous terminons l'étude par deux applications : la reconstruction directe du profil de célérité sans information a prioriet l'estimation de la profondeur relative des instruments.
Modal theory, propagation time, propagation angle, phase velocity, group velocity, beamforming.
Mots clés
Théorie des modes, temps de propagation, angles de propagation, vitessede phase,vitessedegroupe,formation devoies.
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