Browsing Reprints by Type "Reprint (PR)"
Now showing items 201-220 of 228
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Shallow water synthetic aperture sonar: an enabling technology for NATO MCM forces
(NURC, 2007/10)The change in military focus from Cold War doctrine to expeditionary operations in shallower littoral water and the heightened terrorist threat to ports and their approaches, have put increased emphasis on countering ... -
Signal processing for an active sonar system suitable for advanced sensor technology applications and environmental adaptation schemes
(NURC, 2006/08)An overview of the basic elements of an active sonar system in conjunction with a description of the signal processing chain utilized at the NATO Undersea Research Centre for detection and localization of undersea targets ... -
Sub-bands beam-space adaptive beamformer for port-starboard rejection in triplet sonar arrays
(CMRE, 2019/05)This paper addresses the problem of Port-Starboard (PS) beamforming for low-frequency active sonar (LFAS) with a triplet receiver array. The paper presents a new algorithm for sub-bands beam-space adaptive beamforming with ... -
Supporting AUV localisation through next generation underwater acoustic networks: results from the field
(CMRE, 2017/11)This work describes how the localisation of autonomous underwater vehicles can be supported through net-worked acoustic communication. The localisation approach in-cludes timing information within acoustic messages to ... -
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 ... -
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 ... -
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. ... -
Target time smearing with short transmmissions and multipath propagation
(NURC, 2012/04)In active sonar the target echo level is often estimated with a propagation model that adds all multipath arrivals. If the (post-correlator) transmitted pulse is short compared to the multipath time spread then there is ... -
The dynamics of information fusion: synthetic versus misassociation
(NURC, 2006/08)Fusion entails both the association and synthesis of information. If missassociations occur, they obviously undermine the gains won by synthesis, compromising the fusion product. An analytic framework is presented here to ... -
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 ... -
The intrinsic variability of detection range and its implications
(NURC, 2009/12)The range of first detection of an approaching target is among the most important parameters defining sensors and defensive surveillance systems. A demonstration of capability typically consists of staged approaches of a ... -
The relation between the waveguide invariant, multipath impulse response, and ray cycles
(NURC, 2012/04)The waveguide invariant, b, that manifests itself as interference fringes or "striations" in a plot of frequency vs source-receiver separation, is usually thought of as a modal phenomenon. This paper shows that striations ... -
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 ... -
Toward the development of secure underwater acoustic networks
(CMRE, 2019/05)Underwater acoustic networks (UANs) have been recognized as an enabling technology for various applications in the maritime domain. The wireless nature of the acoustic medium makes UANs vulnerable to various malicious ... -
Towards fully autonomous underwater vehicles in ASW scenarios: an adaptive data driven AUV mission management layer
(CMRE, 2019/06)We present an adaptive, data driven Mission Management Layer (MML) to manage the phases (surveillance, track prosecution and target reacquisition) of the mission of AUVs operating as receiver nodes in a multistatic network ... -
Tracking an unknown number of targets using multiple sensors: a belief propagation method
(CMRE, 2019/06)We propose a multisensor method for tracking an unknown number of targets. Low computational complexity and very good scalability in the number of targets, number of sensors, and number of measurements per sensor are ... -
Underwater communications research and development at CMRE
(CMRE, 2019/06)A key to developing autonomous maritime systems for NATO is communication among data gathering platforms below and above the water. However, unlike the mature technologies that are used for terrestrial networks, underwater ... -
Underwater intruder detection sonar for harbour protection: state of the art review and implications
(NURC, 2006/08)Sonar is the sensor of choice for wide-area underwater surveillance because sonar (based on sound waves) typically provides a much larger area of coverage than radar (electromagnetic waves) or video (visible light) can ... -
Underwater optical and acoustic imaging: a time for fusion? a brief overview of the state-of-the-art
(CMRE, 2019/06)Underwater optical imaging has several drawbacks inherent to the physical medium such as light attenuation and turbidity. Sonars try to obviate those issues although, typically, they have lower resolutions. Combining visual ... -
Underwater source localization using a hydrophone-equipped glider
(CMRE, 2014/01)Buoyancy-driven underwater gliders are autonomous underwater vehicles that were originally developed to collect oceanographic data. CMRE is studying the use of this technology for the characterization of denied areas, ...