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The passive mode tomography of the ocean using data from short vertical arrays bent by the ocean currents

Andrey Shurup, Sergey Sergeev, Valentin Burov
2008 Journal of the Acoustical Society of America  
It is shown that the use of the vertical arrays with vector receivers allows a decrease in the accumulation time to one or several hours, depending on the conditions of experiment.  ...  Acoustics 08 Paris 5281 The possible realization of passive ocean tomography based on the widely discussed relation between the Green's function and ambient noise cross-coherence is discussed.  ...  Without special selection of the direction of noise signal arrivals, the coherence function of the fields will allow estimating the additive combination of the Green's functions for opposite directions  ... 
doi:10.1121/1.2934862 fatcat:3gt6f3zdffc2biq5ug5qnvazny

Parametric spatial post-filtering utilising high-order circular harmonics with applications to underwater sound-field visualisation

Vasileios Bountourakis, Leo McCormack, Mathias Winberg, Ville Pulkki
2021 Journal of the Acoustical Society of America  
Beamforming using a circular array of hydrophones may be employed for the task of two-dimensional (2D) underwater sound-field visualisation.  ...  In essence, the proposed method is a reformulation of the cross-pattern coherence (CroPaC) spatial post-filter, which involves calculating the normalised cross-spectral density between two signals originating  ...  ACKNOWLEDGMENTS The authors would like to acknowledge SAAB AB for funding the project and SAAB Kockums AB for providing their expertise and the simulation data of the passive sonar scenarios.  ... 
doi:10.1121/10.0005414 pmid:34241425 fatcat:tajukfirvbgvphkp2ercml72tq

Accurate azimuth estimates from a large aperture hydrophone array using T-phase waveforms

Jeffrey A. Hanson, Holly K. Given
1998 Geophysical Research Letters  
A simple method is described whereby stationto-source azimuths are estimated by fitting a plane wave to envelope functions of T-phases observed on a 5-element hydrophone array around Ascension Island,  ...  azimuths when 3 or more hydrophone elements are used.  ...  We thank David Harris of LLNL, Ronan LeBras of Science Applications International Corporation, and Frank Pilotte and Ellen Herron from the Air Force Technical Applications Center.  ... 
doi:10.1029/97gl53697 fatcat:unsmchmflfeefoimuc4r6lrvtu

Optimization of the Equivalent Source Configuration for the Equivalent Source Method

Lanyue Zhang, Jia Wang, Desen Yang, Bo Hu, Di Wu
2021 Journal of Marine Science and Engineering  
In this paper, an equivalent source configuration method that is simple, effective, and easy to implement, and which based on a tradeoff between the ill condition of the transfer matrix and the adequacy  ...  Finally, the experiments conducted with a cylindrical shell structure verified the validity and practicality of the proposed method.  ...  Conflicts of Interest: The authors declare no conflict of interest.  ... 
doi:10.3390/jmse9080807 fatcat:hhvl2hgylfh5zgzkpx74wnufui

Underwater Localization via Wideband Direction-of-Arrival Estimation Using Acoustic Arrays of Arbitrary Shape

Elizaveta Dubrovinskaya, Veronika Kebkal, Oleksiy Kebkal, Konstantin Kebkal, Paolo Casari
2020 Sensors  
These are ensembles of hydrophones that can be jointly operated in order to, e.g., direct acoustic energy towards a given direction, or to estimate the direction of arrival of a desired signal.  ...  For example, at a signal-to-noise ratio of –20 dB, a 15-element array of opportunity achieves lower average and median localization error (27 m and 12 m, respectively) than a 30-element array with proper  ...  Conflicts of Interest: The authors declare no conflict of interest.  ... 
doi:10.3390/s20143862 pmid:32664398 fatcat:sqfqlnwgvfbdtcjv2tjg4vzqfq

Implementation of adaptive and synthetic-aperture processing schemes in integrated active-passive sonar systems

S. Stergiopoulos
1998 Proceedings of the IEEE  
These schemes are adaptive and synthetic-aperture beam formers that have been shown experimentally to provide improvements in array gain for signals embedded in partially correlated noise fields.  ...  This paper is intended to address issues of implementation of advanced processing schemes in sonar systems and also to serve as a brief overview to the principles and applications of advanced sonar signal  ...  Minimize subject to (22) where is the conventional steering vector based on (10) .  ... 
doi:10.1109/5.659491 fatcat:jk74uoqz7rgupkq7m2qhwh4of4

A New Synthetic Aperture Sonar Processing Method Using Coherence Analysis

Neil Wachowski, Mahmood R. Azimi-Sadjadi
2011 IEEE Journal of Oceanic Engineering  
objects based on properties that are typically not conveyed by conventional SAS images.  ...  Furthermore, this coherence-based SAS-like method does not require the elaborate platform motion estimation and compensation used in conventional SAS.  ...  SAS processing is typically implemented by coherently integrating the data collected by one or more hydrophone elements on an array over a given number of pings to generate the pixels in an image.  ... 
doi:10.1109/joe.2011.2160471 fatcat:upqyjkdn6vc4hlh2n3vvtfrf6e

UNDER WATER ACOUSTIC COMMUNICATIONS

1968 Naval engineers journal (Print)  
The second system combines bit-interleaved coded modulation (BICM), based on a convolutional code and a 16-QAM signal set, with OFDM.  ...  The ...rst system combines Trellis Coded Modulation (TCM) based on an 8-PSK signal set, symbol interleaving and orthogonal frequency-division multiplexing (OFDM).  ...  based on linear combining of the received signals.  ... 
doi:10.1111/j.1559-3584.1968.tb04598.x fatcat:bbhxiqems5hi5fgtqeujllykd4

Buried object scanning sonar

S.G. Schock, A. Tellier, J. Wulf, J. Sara, M. Ericksen
2001 IEEE Journal of Oceanic Engineering  
The sonar operates by illuminating a broad swath of the seabed using a line array of acoustic projectors while acoustic backscattering from the illuminated sediment volume is measured with a planar hydrophone  ...  The output of the planar-hydrophone array undergoes nearfield focusing which allows the sonar to operate near the seabed where target images have the highest and resolution.  ...  in the paper, and funded the coding and testing of fore-aft beamsteering.  ... 
doi:10.1109/48.972111 fatcat:nql22jo7lnedpc6vo2anmsgvxi

Energy-based adaptive focusing of waves: application to noninvasive aberration correction of ultrasonic wavefields

E. Herbert, M. Pernot, G. Montaldo, M. Fink, M. Tanter
2009 IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control  
Based on the measurement of these displacements, this method allows the precise estimation of the phase and amplitude aberrations and consequently the correction of aberrations along the beam travel path  ...  Physique des ondes pour la m decine é INSERM : U979 , Universit Paris-Diderot -Paris VII é , CNRS : UMR7587 , ESPCI ParisTech , Abstract An aberration correction method based on the maximization of the  ...  The coherence between [4 ] [13 ] signals received on two neighbouring elements of the array can be used in order to estimate the delays.  ... 
doi:10.1109/tuffc.2009.1327 pmid:19942526 pmcid:PMC3045085 fatcat:5g7ivxjpevgntmrhx6fmzvsrsa

Improvement of Detection and Localization Performance using the Receiving Array Response Difference between Ocean Noise and Signal in Shallow Water

Tongwei Zhang, Guangjie Han, Zeren Zhou, Jinfang Jiang, Lei Shu
2019 IEEE Access  
Based on the results, three conditions for the existence of the groove in the receiving array response are obtained: 1) a gradient in the sound velocity profile, 2) an SVLA in a water column in which the  ...  The environmental effects of the shape of the sound velocity profile and geo-acoustic properties of the seabed on the receiving array response are analyzed.  ...  IMPROVEMENT OF OSNR The coherence and directionality of the ocean noise depend on the noise-source distribution and environmental parameters in shallow water.  ... 
doi:10.1109/access.2019.2930063 fatcat:6eh3iyhmsbh6bdihumttuube6y

Design and Experimental Validation of a USBL Underwater Acoustic Positioning System

Joel Reis, Marco Morgado, Pedro Batista, Paulo Oliveira, Carlos Silvestre
2016 Sensors  
Let d ∈ R3 be a unit vector that represents the direction of the source expressed in {B}.  ...  Furthermore, the implemented acoustic communications between the transponders and the USBL array (or arrays), which relies on Direct Sequence Spread Spectrum (DSSS) modulated signals, allows for operations  ... 
doi:10.3390/s16091491 pmid:27649181 pmcid:PMC5038764 fatcat:evberognrnazzccdeedwsk6egq

The Acoustic Detection of Ultra High Energy Neutrinos [article]

J. Perkin
2008 arXiv   pre-print
We find that detectors encompassing thousands of cubic kilometres are required, with a minimum of 100 hydrophones per kilometre cubed, in order to observe the flux of neutrinos predicted by the attenuation  ...  Additionally a qualitative analysis of the first acoustic data recorded by the Rona hydrophone array off the north-west coast of Scotland is reported.  ...  flux limit based on their work on a United States Navy hydrophone array located in the Tongue of the Ocean, a deep basin situated near the Bahamas.  ... 
arXiv:0801.0991v1 fatcat:ziwi5banjrh2pndego5jrmruk4

Flow and swell noise in marine seismic data

Thomas Elboth, Bjørn Anders Reif, Øyvind Andreassen
2009 Geophysics  
In addition, a MEMS vector sensor would solve the left-right ambiguity troubling hydrophone systems today.  ...  Figure 2 . 3 : 23 Image a): Snapshot from a direct numerical simulation of channel flow Figure 2 . 5 : 25 Parts of a hydrophone array during manufacturing.  ...  .) • A proof of concept, based upon both simulations and practical measurements that superhydrophobic surface coatings can be used to reduce both drag and flow-noise on seismic streamer arrays.  ... 
doi:10.1190/1.3078403 fatcat:4o6vcaiinbhvbjkgyk2xql6a6e

Single-mode excitation in the shallow-water acoustic channel using feedback control

J.R. Buck, J.C. Preisig, M. Johnson, J. Catipovic
1997 IEEE Journal of Oceanic Engineering  
The source array consists of 10 omni-directional point sources, and the feedback array of 19 hydrophones.  ...  Specifically, they were interested in finding a signal which when transmitted from a single source through a given channel would give an "impulse-like" signal at a single receiving hydrophone.  ...  Based on t his estimate, it computes the best set of source array weights w to get the desired pressure vector Pd • After exciting the channel using w , the algorithm compares the observed pressure vector  ... 
doi:10.1109/48.585947 fatcat:qzi5ibf6undtxip4w2roasfl3i
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