An experimental demonstration of blind ocean acoustic tomography

Jesus, S. M.; Soares, C.; Coelho, Emanuel; Picco, Paola

doi:10.1121/1.2165070

Cited by 15 publications

(5 citation statements)

References 25 publications

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“…Assuming that the emitted noise is a unknown random process measured by a single sensor, correlation with the emitted signal or between measurements from several sensors [17][18][19][20][21][22][23] can not be used to pre-process the data and extract some observables. To cope with these limitations, we first compute the received level of the measurements.…”

Section: B Channel Propagation Featuresmentioning

confidence: 99%

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Passive geoacoustic inversion with a single hydrophone using broadband ship noise

Gervaise

Kinda

Bonnel

et al. 2012

The Journal of the Acoustical Society of America

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An inversion scheme is proposed, relying upon the inversion of the noise of a moving ship measured on a single distant hydrophone. The spectrogram of the measurements exhibits striations which depend on waveguide parameters. The periodic behavior of striations versus range are used to estimate the differences of radial wavenumber between couples of propagative modes at a given frequency. These wavenumber differences are stacked for several frequencies to form the relative dispersion curves. Such relative dispersion curves can be synthesized using a propagation model feeded with a bottom geoacoustic model. Inversion is performed by looking for the bottom properties that optimize the fit between measured and predicted relative dispersion curves. The inversion scheme is tested on simulated data. The conclusions are twofold: (1) a minimum 6 dB signal to noise ratio is required to obtained an unbiased estimate of compressional sound speed in the bottom with a 3 m s(-1) standard deviation; however, even with low signal to noise ratio, the estimation error remains bounded and (2) in the case of a multi-layer bottom, the scheme produces a single depth-average compressional sound speed. The inversion scheme is applied on experimental data. The results are fully consistent with a core sample measured around the receiving hydrophone.

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Section: B Channel Propagation Featuresmentioning

confidence: 99%

“…CSDM are often computed over a few narrow frequency bands characterizing ship noise. [17][18][19][20][21] Sometimes, the CSDM are averaged over several frequency bandwidths. 22,23 However, the CSDM does not exploit the whole broadband nature of the noise radiated by a ship and the range aperture created by its movement.…”

Section: Introductionmentioning

confidence: 99%

Passive geoacoustic inversion with a single hydrophone using broadband ship noise

Gervaise

Kinda

Bonnel

et al. 2012

The Journal of the Acoustical Society of America

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“…Fig. 2(b) depicts the filtered acoustic noise in the 30 -460 Hz band, where the discrete tones emanating from the NRP D. Carlos are clearly visible [10]. Fig.…”

Section: Analysis Of the Radar'07 Data Setmentioning

confidence: 99%

Acoustic channel frequency response estimation using sources of opportunity

Santos

Felisberto

Jesus

2016

2016 IEEE/OES China Ocean Acoustics (COA)

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Abstract-This work addresses the usage of ship radiated noise to estimate the ocean acoustic water propagation channel response between two vertical line arrays. We derive an expression for the frequency response channel estimate using a normal mode development based on cross-correlation methods, in a similar way as Roux et al. [1]. Its applicability and limitations in simulated and real conditions is discussed. Simulations are conducted using the normal mode model KRAKEN, based on the experimental setup and environmental parameters gathered during the RADAR'07 sea trial, off the west coast of Portugal, in July of 2007. In this sea trial two drifting vertical line arrays with 16 and 8 hydrophones were deployed in a range independent bathymetric area, at 300 m and 1.3 km distance from the Research Vessel NRP D. Carlos I, whose track then moved away from the arrays, radiating noise in the frequency band bellow 750 Hz. The wave fronts structure, obtained from actual acoustic data of the above referred sea trial, reveals agreement with the simulations obtained with the proposed approach. These results suggest the feasibility of the method for future application in a passive ocean acoustics tomography framework to the estimation of sound speed perturbations in the water column.

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“…It was also possible to transfer acoustic data from the AOB1 via ftp, for on-board online inversion. The inversion software was based on code previously developed for blind ocean acoustic tomography (Jesus et al, 2006), with different settings for the parameter search bounds and the genetic algorithm conversion parameters, taking into account that the source position was approximately known, and that only very few hydrophones were available.…”

Section: The Acoustic Oceanographic Buoymentioning

confidence: 99%

Environmental and acoustic assessment: The AOB concept

Martins

Soares

Jesus

2008

Journal of Marine Systems

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The requirement for rapid environmental assessment has motivated the development of prediction tools, which allow the observation and prediction in very short notice, of the ocean evolution in an interval up to 3-4 weeks, in given littoral areas. Complex systems exist nowadays, where multidimensional quantities like the oceanographic-biogeochemical-optical-acoustic fields, are tracked in time, melding measures and models of some or all the involved quantities. At some point in the prediction system, the acoustic forecast is computed by acoustic propagation models taking as input the environmental forecast. Inevitably, the error of the acoustic forecast as given by the model output, originates from at least two error sources. The first is the environmental forecast error. The second is due to the model inaccuracies, and to the dependence of propagation on parameters not dealt with by the prediction system, like geometric or geo-acoustic properties. The acoustic community has developed a large number of acoustic inversion systems -based on e.g. matched-field processors or travel-time tomography -from which one can learn that an accurate acoustic simulation requires feeding the acoustic model with an environment which differs from the actual environment by a certain gap. This requires that the environmental forecast as given by ocean prediction systems be gap-compensated, prior to its inclusion in the acoustic environmental input. This paper puts the environmental gap in evidence, considering environmental forecasts, and historical and inverted data, to define heterogeneous environmental inputs to the propagation model. The corresponding acoustic outputs are compared to actual data from the MREA '03 sea trial. It is observed that acoustic inversion can play a significant role in converting the environmental forecast into the acoustic forecast.

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An experimental demonstration of blind ocean acoustic tomography

Cited by 15 publications

References 25 publications

Passive geoacoustic inversion with a single hydrophone using broadband ship noise

Passive geoacoustic inversion with a single hydrophone using broadband ship noise

Acoustic channel frequency response estimation using sources of opportunity

Environmental and acoustic assessment: The AOB concept

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