Searched for: subject%3A%22Synthetic%255C%2Baperture%255C%2Bsonar%22
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Synnes, S.A.V. (author), Hunter, A.J. (author), Hansen, R.E. (author), Sabo, T.O. (author), Callow, H.J. (author), van Vossen, R. (author), Austeng, A. (author)
Wideband and widebeam synthetic aperture sonar (SAS) can provide information on the frequency- and aspect dependent scattering in a scene. We suggest an approach to predict the quality of the sensor data over the available frequencies and aspect angles. We relate the typical spatial domain quality metrics to their wave number domain (WD)...
article 2017
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Duijster, A.J. (author), Hunter, A. (author), van Vossen, R. (author), Beckers, A.L.D. (author)
Detection of unexploded ordnance is challenging in the underwater environment, particularly when object burial occurs. A capability to detect buried targets has been demonstrated previously using TNO’s MUD low frequency sediment-penetrating sonar and other similar sonars. However, the high clutter rates encountered in practice have the potential...
conference paper 2014
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Hunter, A.J. (author), van Vossen, R. (author), Quesson, B.A.J. (author), Beckers, A.L.D. (author)
The remediation of underwater unexploded ordnance (UXO) requires a capability to detect and classify objects on or beneath the seafloor. This can be facilitated partly by use of modern high-frequency imaging sonar. However, this technology is limited in two respects: 1) the high frequencies employed by these systems cannot penetrate into the...
conference paper 2013
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Bonnett, B. (author), Hayes, M. (author), Hunter, A. (author)
Coherent change detection between multiple synthetic aperture sonar (SAS) images is reliant on the images being co-registered with sub-pixel accuracy. In this paper we suggest a technique using available navigation data to reconstruct the images onto a common grid. Data obtained using the MUD SAS system is used to demonstrate this method. We...
conference paper 2013
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Hunter, A.J. (author), van Vossen, R. (author)
A method is presented for separating the broadband acoustic target response from the background seafloor reverberation based on the multi-look synthetic aperture sonar (SAS) image coherence. The method computes the coherence in the wavelet domain and uses this to distinguish between the target and background, which are assumed to be...
conference paper 2013
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van Vossen, R. (author), Quesson, B.A.J. (author), Beckers, A.L.D. (author), Zampolli, M. (author), Colin, M.E.G.D. (author), Hunter, A.J. (author)
Naval mines, underwater improvised explosive devices (UW-IEDs), and underwater unexploded ordnance (UW-UXO) are concerns for harbour security. In conditions without burial, existing commercial systems, such as the REMUS unmanned underwater vehicle equipped with a (very) high frequency side scan sonar (900/1800 kHz), may be deployed for detection...
conference paper 2012
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Beckers, A.L.D. (author), van Vossen, R. (author), Vlaming, G. (author)
Naval mines and underwater improvised explosive devices in harbors can halt or block maritime transport, causing local disruptions that can impact national and regional economies considerably. Securing harbors against such threats is implemented in the Netherlands through cooperation between civil and military authorities. Existing commercial...
article 2012
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Hunter, A.J. (author), van Vossen, R. (author), Quesson, B.A.J. (author), Colin, M.E.G.D. (author), Zampolli, M. (author), Beckers, A.L.D. (author)
Sidescan high-frequency (HF) sonar (i.e., with frequencies higher than 100 kHz) is ideally suited for providing high-resolution images of the seafloor. However, since sound does not penetrate into the sediment at these frequencies, such systems cannot be used for the detection of buried objects, such as naval mines, improvised explosive devices ...
conference paper 2012
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Hayes, M. (author), Hunter, A.J. (author)
Bathymetric estimation from multiple synthetic aperture sonar (SAS) images is challenging for shallow water environments with low frequencies. This is due to the multipath echoes corrupting the desired direct-path echoes. In an attempt to suppress some of these multipaths, the MUD synthetic aperture sonar developed at TNO has a sixteen element...
conference paper 2012
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Williams, K.L. (author), Kargl, S.G. (author), Thorsos, E.I. (author), Burnett, D.S. (author), Lopes, J.L. (author), Zampolli, M. (author), Marston, P.L. (author), TNO Defensie en Veiligheid (author)
Understanding acoustic scattering from objects placed on the interface between two media requires incorporation of scattering off the interface. Here, this class of problems is studied in the particular context of a 61 cm long, 30.5 cm diameter solid aluminum cylinder placed on a flattened sand interface. Experimental results are presented for...
article 2010
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Quesson, B.A.J. (author), Sabel, J.C. (author), Bouma, H. (author), Dekker, R.J. (author), Lengrand-Lambert, J. (author), TNO Defensie en Veiligheid (author)
The future of Mine Countermeasures (MCM) operations lies with unmanned platforms where Automatic Target Recognition (ATR) is an essential step in making the mine hunting process autonomous. At TNO, a new ATR method is currently being developed for use on an Autonomous Underwater Vehicle (AUV), using SAS images of known targets in an operational...
conference paper 2010
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Groen, J. (author), Hansen, R.E. (author), Callow, H.J. (author), Sabel, J.C. (author), Sæbø, T.O. (author), TNO Defensie en Veiligheid (author)
Abstract—A shadow cast by an object on the seafloor is important information for target recognition in synthetic aperture sonar (SAS) images. Synthetic aperture imaging causes a fundamental limitation to shadow clarity because the illuminator is moved during the data collection. This leads to a blend of echo and shadow, or geometrical fill-in in...
article 2009
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TNO Defensie en Veiligheid (author), Groen, E.L. (author), Nooij, S.A.E. (author), Bos, J.E. (author)
At TNO research is ongoing on neuro-vestibular adaptation to altered G-levels. It is well-known that during the first days in weightlessness 50-80% of all astronauts suffer from the Space Adaptation Syndrome (SAS), which involves space motion sickness, spatial disorientation and motion illusions. After return on Earth the problems re-appear, but...
conference paper 2008
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TNO Defensie en Veiligheid (author), Nooij, S.A.E. (author), Bos, J.E. (author), Groen, E.L. (author), Bles, W. (author), Ockels, W.J. (author)
During the first days in space, i.e., after a transition from 1G to 0G, more than 50% of the astro- (and cosmonauts) suffer from the Space Adaptation Syndrome (SAS).The symptoms of SAS, like nausea and dizziness, are especially provoked by head movements. Astronauts have mentioned close similarities between the symptoms of SAS and the symptoms...
article 2007
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Hansen, R.E. (author), Callow, H.J. (author), Saebo, T.O. (author), Groen, J. (author), Quesson, B.A.J. (author), Sabel, J.C. (author), TNO Defensie en Veiligheid (author)
An acoustic simulator is vital for the development of sonar data processing. The most important features in the TNO 3D simulator SIMONA are detailed target response including shadow, reverberation modelling, sonar properties and multipath. The verification and development of SIMONA was realized alongside with a wide range of measurements in a...
conference paper 2005
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Sabel, J.C. (author), Groen, J. (author), Quesson, B.A.J. (author), TNO Defensie en Veiligheid (author)
The acoustic shadow of a target is a strong classification clue in naval mine hunting. A shadow of bottom targets appears at relatively short ranges (≤ about 200 m) in high resolution images from sidescan or synthetic aperture sonar (SAS), against a background of sea floor reverberation. In SAS however, definition of the shadow reduces with...
conference paper 2005
document
Colin, M.E.G.D. (author), Groen, J. (author), Quesson, B.A.J. (author), TNO Fysisch en Elektronisch Laboratorium (author)
Although Low Frequency Active Sonar (LFAS) is considered one of the best means of detection and localization of a submarine in shallow water, the use of an active system is not always possible for tactical reasons. It is therefore interesting to include a passive mode in these systems by using the receiving array as a passive array. However,...
conference paper 2004
document
Groen, J. (author), Beerens, S.P. (author), Doisy, Y. (author), TNO Fysisch en Elektronisch Laboratorium (author)
Anti Submarine Warfare (ASW) is more and more focused toward shallow water environments. Many complications have come up for ASW sonar performance as a result of this. The problem that is tackled in this article is the performance loss due to the shape and motion of the sonar during a maneuver. Standard beamforming in towed sonar arrays is based...
conference paper 2004
document
Groen, J. (author), Hansen, R.E. (author), Sabel, J.C. (author), TNO Fysisch en Elektronisch Laboratorium (author)
In the next generation of mine hunting sonars, in particular on Autonomous Underwater Vehicles (AUVs), Synthetic Aperture Sonar (SAS) will play an important role. The benefit of SAS is to increase resolution and signal-tonoise ratio by coherent processing of successive pings. A challenge in SAS is the computational load. This is caused primarily...
conference paper 2003
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Colin, M.E.G.D. (author), Groen, J. (author), TNO Fysisch en Elektronisch Laboratorium (author)
An important issue in research on passive ASW operations is improvement in signal-to-noise ratio (SNR) and bearing resolution for targets emitting low frequency signals. One of the techniques believed to improve these characteristics is Synthetic Aperture Sonar (SAS). The method is based on the artificial enlargement of a sonar array by...
conference paper 2002
Searched for: subject%3A%22Synthetic%255C%2Baperture%255C%2Bsonar%22
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