Modeling Propagation and Reverberation Sensitivity to Oceanographic and Seabed Variability

LePage, Kevin D.

doi:10.1109/joe.2006.875095

Cited by 20 publications

(3 citation statements)

References 6 publications

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“…Thus, modeling the acoustic communication channel in underwater configuration has been the target of multiple studies where the effect of Sound Speed Profile (SSP) onto the propagating acoustic signal is addressed [91][92][93][94][95][96]. In general, factoring in the SSP variability in underwater environments yields better estimates of acoustic propagation paths and eventually improves localization accuracy [97]. Moreover, a recent work is targeting to localize a swarm of underwater autonomous vehicles [98].…”

Section: Pa-enabled Underwater Localizationmentioning

confidence: 99%

Cross-Medium Photoacoustic Communications: Challenges, and State of the Art

Mahmud

Islam

Ahmed

et al. 2022

Sensors

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The current era is notably characterized by the major advances in communication technologies. The increased connectivity has been transformative in terrestrial, space, and undersea applications. Nonetheless, the water medium imposes unique constraints on the signals that can be pursued for establishing wireless links. While numerous studies have been dedicated to tackling the challenges for underwater communication, little attention has been paid to effectively interfacing the underwater networks to remote entities. Particularly it has been conventionally assumed that a surface node will be deployed to act as a relay using acoustic links for underwater nodes and radio links for air-based communication. Yet, such an assumption could be, in fact, a hindrance in practice. The paper discusses alternative means by allowing communication across the air–water interface. Specifically, the optoacoustic effect, also referred to as photoacoustic effect, is being exploited as a means for achieving connectivity between underwater and airborne nodes. The paper provides background, discusses technical challenges, and summarizes progress. Open research problems are also highlighted.

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Section: Pa-enabled Underwater Localizationmentioning

confidence: 99%

Cross-Medium Photoacoustic Communications: Challenges, and State of the Art

Mahmud

Islam

Ahmed

et al. 2022

Sensors

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“…The impacts of this uncertainty and variability have been studied in the context of various propagation models and experiments (Flatté et al 1979;Krolik 1992;Finette 2006), and analytic computations of the sensitivity of propagation and reverberation in a waveguide on oceanographic and some geoacoustic (sound speed and attenuation, or complex sound speed) parameters have also been developed (LePage 2006). One method that may be used to compute sensitivity, described in , uses Monte Carlo sampling to draw random model parameter perturbations δm j from a Gaussian distribution with mean m j based on measured geoacoustic and oceanographic parameters.…”

Section: Uncertainty and Acoustic Propagationmentioning

confidence: 99%

Sensitivity of acoustic propagation to uncertainties in the marine environment as characterized by various rapid environmental assessment methods

Pecknold

Osler

2011

Ocean Dynamics

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Accurate sonar performance prediction modelling depends on a good knowledge of the local environment, including bathymetry, oceanography and seabed properties. The function of rapid environmental assessment (REA) is to obtain relevant environmental data in a tactically relevant time frame, with REA methods categorized by the nature and immediacy of their application, from historical databases through remotely sensed data to in situ acquisition. However, each REA approach is subject to its own set of uncertainties, which are in turn transferred to uncertainty in sonar performance prediction. An approach to quantify and manage this uncertainty has been developed through the definition of sensitivity metrics and Monte Carlo simulations of acoustic propagation using multiple realizations of the marine environment. This approach can be simplified by using a linearized two-point sensitivity measure based on the statistics of the environmental parameters used by acoustic propagation models. The statistical properties of the environmental parameters may be obtained from compilations of historical data, forecast conditions or in situ measurements.During a field trial off the coast of Nova Scotia, a set of environmental data, including oceanographic and geoacoustic parameters, were collected together with acoustic transmission loss data. At the same time, several numerical models to forecast the oceanographic conditions were run for the area, including 5-and 1-day forecasts as well as nowcasts. Data from the model runs are compared to each other and to in situ environmental sampling, and estimates of the environmental uncertainties are calculated. The forecast and in situ data are used with historical geoacoustic databases and geoacoustic parameters collected using REA techniques, respectively, to perform acoustic transmission loss predictions, which are then compared to measured transmission loss. The progression of uncertainties in the marine environment, within and between different REA categories, and the consequences on acoustic propagation are examined.

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“…The main factor reducing the accuracy of field simulation in the ocean acoustic waveguide is the inevitable inaccuracy of environmental model used in solving the wave equation. When analyzing this issue, the main attention is usually paid to questions on how the uncertainty in environmental parameters manifests itself in field predictions [1,2] and in solutions of inverse problems [3,4]. This work is devoted to another aspect of the problem of inaccurate knowledge of the environment model.…”

Section: Introductionmentioning

confidence: 99%

Stable components of sound fields in the ocean

Virovlyansky

2017

The Journal of the Acoustical Society of America

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A method is proposed for finding the wave field components which are weakly sensitive to the sound speed perturbation in the ocean acoustic waveguides. Such a component is formed by a narrow beam of rays whose spread in vertical direction, up to the observation range, remains less than the vertical scale of perturbation. These rays pass through practically the same inhomogeneities and therefore their phases are incremented by the same amount. If the ray amplitudes vary insignificantly, then (i) the stable components of the monochromatic field in the perturbed and unperturbed waveguide differ by only a constant phase factor, and (ii) in the case of transient wave field the perturbation causes only an additional time delay of the stable component as a whole. It is shown how the stable components can be selected from the total wave field using the field expansions in the coherent states and in the normal modes. The existence of stable components is demonstrated by numerical simulation of sound field in a deep water waveguide. It turns out, that even though the assumptions (i) and (ii) are not met exactly, the stable components in the perturbed and unperturbed waveguides are quite close.

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Modeling Propagation and Reverberation Sensitivity to Oceanographic and Seabed Variability

Cited by 20 publications

References 6 publications

Cross-Medium Photoacoustic Communications: Challenges, and State of the Art

Cross-Medium Photoacoustic Communications: Challenges, and State of the Art

Sensitivity of acoustic propagation to uncertainties in the marine environment as characterized by various rapid environmental assessment methods

Stable components of sound fields in the ocean

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