Eigenray finding and time series simulation in a layered-bottom ocean

Westwood, Evan K.; Vidmar, Paul J.

doi:10.1121/1.394571

Cited by 47 publications

(12 citation statements)

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“…It may be possible to use a ray tracer if the acoustic bottom interactions are treated correctly. 28,29 ͑2͒ Geometry-The ideal measurement geometry will also need to be determined as it is likely that parameters like array length, tow depths, and signal types will need to be optimized to improve estimates of the seabed properties. ͑3͒ Cost functions-Cost functions have different sensitivities that de-TABLE III.…”

Section: Discussionmentioning

confidence: 99%

Range-dependent seabed characterization by inversion of acoustic data from a towed receiver array

Siderius

Nielsen

Gerstoft

2002

The Journal of the Acoustical Society of America

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The MAPEX2000 experiments were conducted in the Mediterranean Sea in March, 2000 to determine seabed properties using a towed acoustic source and receiver array. Towed systems are advantageous because they are easy to deploy from a ship and the moving platform offers the possibility for estimating spatially variable (range-dependent) seabed properties. In this paper, seabed parameters are determined using a matched-field geoacoustic inversion approach with measured, towed array data. Previous research has successfully applied matched-field geoacoustic inversion techniques to measured acoustic data. However, in nearly all cases the inverted data were collected on moored, vertical receiver arrays. Results here show that seabed parameters can also be extracted by inverting acoustic measurements from a towed array of receivers, and these agree with those inverted using data received simultaneously on a vertical array. These findings imply that a practical technique could be developed to map range-dependent seabed parameters over large areas using a towed acoustic system. An example of such a range-dependent inversion is given using measurements from the MAPEX2000 experiments.

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Section: Discussionmentioning

confidence: 99%

Range-dependent seabed characterization by inversion of acoustic data from a towed receiver array

Siderius

Nielsen

Gerstoft

2002

The Journal of the Acoustical Society of America

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“…24 A seabed containing many thin sediment layers is known to cause distortion of broadband signals resulting from multiple reflections of acoustic rays with sub-bottom interfaces. 26 However, at low frequencies, the long wavelengths are insensitive to the details of thin layers and interact with an effectively continuous velocity profile. The accuracy of describing the layered ooze found in the Catoche Tongue with a simplified sediment representation was assessed by comparing the modeled time series of the direct (non-horizontally refracted) arrivals in a 5 Hz band centered at 25 Hz using a 2D normal-mode model.…”

Section: B Environmental Representationmentioning

confidence: 99%

Evidence of three-dimensional acoustic propagation in the Catoche Tongue

Sagers

Ballard

Knobles

2014

The Journal of the Acoustical Society of America

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This paper presents observations of two classes of acoustic arrivals recorded on a sparsely populated vertical line array (VLA) moored in the center of the Catoche Tongue, a major reentrant in the Campeche Bank in the southeastern Gulf of Mexico. The acoustic signals were generated by signals underwater sound (SUS) located 50-80 km from the VLA. The first class of arrivals was identified as resulting from a direct (non-horizontally refracted) path. Then following a quiescent period, a second, more diffuse class of arrivals is observed and is believed to be the result of horizontal refraction from the margin of the Tongue. A spectral analysis of the measured data revealed that both classes of arrivals were characterized by the source spectrum associated with SUS. Additionally, the difference in time between the onset of the first and second class of arrivals observed as a function of range from the VLA is consistent with the relative difference in the length of the direct and refracted paths. The observations are further supported by a three-dimensional (3D) acoustic propagation computation that reproduces many of the features of the measured data and provides additional insight into the details of the 3D propagation.

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“…Many different techniques in this category tend to be informal and often partially empirical solution based. One example of the solution for semi-coherent transmission loss calculation is given by [13] …”

Section: Transmission Lossmentioning

confidence: 99%

Acoustic propagation properties of underwater communication channels and their influence on the medium access control protocols

Venkatesan

2012

2012 IEEE International Conference on Communications (ICC)

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Underwater acoustic communications in the ocean is complicated as the acoustic signals may be attenuated, distorted and delayed. In this paper, we review the underwater acoustic signal propagation properties in terms of sound speed profile, spreading loss and absorption loss. We study and compare different approaches on the calculation of signal transmission loss in the water, more specifically, the ray theory model approach and the semi-empirical formula approach. Using the Acoustic Toolbox, we compare their performance under different environmental parameters, including the sound source depth, bathymetry data, and the horizontal distance between the sound source and receiver. Furthermore, in order to obtain how the acoustic propagation characteristics will affect the performance of medium access control (MAC) protocol, we adopt pure ALOHA protocol and use network simulator ns-2 to study the throughput performance under both shallow water and deep ocean conditions. Our results indicate that the transmission loss in the shallow water is close to the result of semi-empirical formula with transition region (k = 1.5), which is close to the result of semi-empirical formula with spherical spreading loss (k = 2) in deep water.

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Eigenray finding and time series simulation in a layered-bottom ocean

Cited by 47 publications

References 0 publications

Range-dependent seabed characterization by inversion of acoustic data from a towed receiver array

Range-dependent seabed characterization by inversion of acoustic data from a towed receiver array

Evidence of three-dimensional acoustic propagation in the Catoche Tongue

Acoustic propagation properties of underwater communication channels and their influence on the medium access control protocols

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