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Experimental results of 300 kHz shallow water synthetic aperture sonar
(NURC, 2007/11)The design of a shallow water synthetic aperture sonar (SAS) requires an understanding of key system and environmental issues. The main factors which limit SAS performance are micronavigation accuracy, where micronavigation ... -
Adaptive sub-band processing in active detection and tracking
(NURC, 2007/11)Broadband active systems have the potential to increase detection performance in reverberation-limited areas through increased signal bandwidth, i.e. small resolution cell. However, large bandwidth could over-resolve the ... -
Through-the-sensor geoacoustic inversion along a towed horizontal line array: results from real data set in the Mediterranean sea
(NURC, 2007/12)The assessment of active sonar performances in shallow water strongly depends on the environmental conditions. Of most importance, bottom properties are known to strongly affect the forward acoustic propagation and ... -
At-sea measurements of acoustic elastic scattering by a 1.5m-long cylinder made of composite materials
(NURC, 2007/12)Monostatic and bistatic acoustic scattering measurements were performed on solid-filled fibreglass objects (a sphere and a cylinder with hemispherical endcaps) deployed proud on a sandy seabed and insonified by a rail-mounted ... -
Tank measurements of elastic scattering by a resin-filled fiberglass spherical shell
(NURC, 2007/12)Acoustic elastic scattering measurements were conducted in a tank on a 6cm radius fibreglass spherical shell filled with a low-shear-speed epoxy resin. Preliminary measurements were conducted also on the void shell before ... -
On the integration of through-the-sensor geoacoustic inversion techniques for environmental adaptation schemes in low frequency active sonars
(NURC, 2007/12)The environmental conditions in shallow water areas are known to strongly affect the performances of low frequency active sonars (LFAS). In particular, interactions of the acoustical field with the seabed interface have ... -
Review of target strength information for waterside security applications
(NURC, 2008)Estimates of the target strength of objects, such as for example scuba tanks and swimmer delivery vehicles, are parameters of interest in all phases of the design of waterside security systems. Results of numerical target ... -
Heterogeneous underwater networks for ASW: technology and techniques
(NURC, 2008/06)NATO's research and technology objectives for anti-submarine warfare (ASW) include persistent scalable heterogeneous wide-area surveillance networks for the littoral environment. Network and system design considerations ... -
The effectiveness of a system-of-systems for countering asymmetric maritime threats in ports and harbours
(NURC, 2008/09)A small boat loaded with explosives has been used by terrorists to attack military and civilian maritime surface vessels at berth or at anchor. For example, suicide bombers attacked the USS Cole using a small boat while ... -
Security versus defence: dual use from a system requirement perspective
(NURC, 2008/09)The developers of defence technologies in both industry and national laboratories carried their culture for military system development into the evolving security mission, even for systems that are to be used by civilian ... -
Geoacoustic inversion using multipath pulse shape
(NURC, 2008/09)Experimental data, measured in a shallow water region of the Mediterranean Sea, are used to show that the variation of received intensity with time is well described by existing expressions [Harrison and Nielsen, J. Acoust. ... -
Target detection and location with ambient noise
(NURC, 2008/09)By placing a vertical array in an ambient noise field and forming an upward and a downward beam one obtains two time series which can be cross correlated to reveal a subbottom profile of the seabed [Siderius et al., J. ... -
A comparative analysis of side-looking sonars for rapid classification of underwater intruders
(NURC, 2008/09)One aspect of NURC's 2008 efforts in port protection involves building a prototype system for countering a subsurface threat. Such a capability against underwater intruders in ports requires surveillance of the underwater ... -
Tank measurements of scattering from a resin-filled fibreglass spherical shell with internal flaws
(NURC, 2008/09)This paper presents results of acoustic inversion and structural health monitoring achieved by means of low to midfrequency elastic scattering analysis of simple, curved objects, insonified in a water tank. Acoustic elastic ... -
Automatic change detection for the monitoring of cluttered underwater areas
(NURC, 2008/09)Automating the surveillance of cluttered underwater areas (such as ports) poses several problems, the main one being the high number of contacts that any automatic target recognition (ATR) system will produce when surveying ... -
NATO Undersea Research Centre marine mammal risk mitigation rules and procedures
(NURC, 2008/12)The goals of the NATO Marine Mammal Risk Mitigation include the development of risk mitigation protocols, computer tools, and in-water devices to provide risk mitigation before sonar experiments so to avoid potential ... -
The Barny program: fourteen years of NURC-NRL collaboration
(NURC, 2009/05)Shallow ocean environments, with their rapid variability, short spatial scales and often intense fishing, pose a special challenge for physical oceanographic study. Since 1995, a series of collaborative programs between ... -
2008 Research and Technology Highlights
(NURC, 2009/06) -
NATO Undersea Research Centre marine mammal risk mitigation rules and procedures
(NURC, 2009/11)The NATO Undersea Research Centre (NURC) Marine Mammal Risk Mitigation Rules and Procedures provides the policy and the procedures to scientific planners, Scientists-in-Charge (SIC), researchers and the Masters of NURC ... -
Measurements and modelling of high-frequency acoustic scattering by a rough seafloor and sea surface
(NURC, 2009/12)Acoustic scattering by a rough, possibly dynamic interface is experimentally studied by insonifying the seabed and the sea surface at high frequency at various incidentangles. A directional source working at 300 kHz was ...