Sound speed profile characterization by the image source method
TypeArticles dans des revues avec comité de lecture
This paper presents the first results of an imaging technique that measures the geoacoustic structure of a seafloor in shallow water areas. The devices used were a broadband 100 Hz–6 kHz acoustic source towed by a ship and a vertical array. Among all the acoustic paths existing in the water column, two are used: the direct one and the seabed-reflected one, the latter being composed of the reflections from the seafloor’s surface as well as that from each buried layer. Due to the good time resolution of the signal and to the short range configuration, the reflected signal can be modeled as a sum of contributions coming from image sources relative to the seabed layers. The seabed geometry and the sound speed profile can then be recovered with the detection and localization of these image sources. The map of the image sources is obtained by a function that combines back-propagation of signals and knowledge of the emitted pulse. The thickness and sound-speed of each layer is finally obtained by a position analysis of the image sources. The results obtained by this data-driven algorithm on both at-sea and synthetic data are satisfactory.
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PINSON, Samuel; CORDIOLI, Julio; GUILLON, Laurent (Acoustical Society of America, 2016)In the context of sediment characterization, layer interface roughnesses may be responsible for sound-speed profile measurement uncertainties. To study the roughness influence, a three-dimensional (3D) modeling of a layered ...
PINSON, Samuel; GUILLON, Laurent; HOLLAND, Charles (The Acoustical Society of America, 2013)This paper presents a range dependent sediment sound speed profile measurement obtained using the image source method. This technique is based on the analysis of the seafloor reflected acoustic wave as a collection of image ...
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GUILLON, Laurent; HOLLAND, Charles; BARBER, Christopher (IEEE, 2011)Direct path measurements of a single-bottom interacting path on a vertical array are used to probe the seabed structure. The phase of the cross-spectrum, commonly used in engineering acoustics, permits examination of the ...
GUILLON, Laurent; BOUDRAA, Abdel-Ouahab (The Acoustical Society of America, 2014)This letter presents an improvement of the image source method (ISM) for geoacoustic inversion. The new algorithm is based on the Teager-Kaiser Energy Operator which ampli es the discontinuities in signals while the soft ...