Browsing by Title
Now showing items 560-579 of 882
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Oceanographic data from the southern Tyrrhenian Sea: August to October 1984: Part 1 - Floats and moored instruments: Part 2 - Hydrography
(NATO. SACLANTCEN, 1988/02)A SACLANTCEN observational programme in the Southern Tyrrhenian Sea comprised a sequence of three cruises during the period August to November 1984. The primary purpose was to investigate the late summer water-mass variability ... -
Oceanographic field estimates from remote sensing and glider fleets
(CMRE, 2014/01)This work investigates the merging of temperature observations from a glider fleet and remote sensing, based on a field experiment conducted in an extended coastal region offshore La Spezia, Italy, in August 2010. Functional ... -
Oceanographic measurements of the West Black Sea: November 26 to December 14, 1995
(NATO. SACLANTCEN, 1998/06)Mediterranean water inflow into the Black Sea is investigated using acoustic and oceanographic data obtained in the Black Sea exit region. Temporal and spatial variability in the flow and their relation to atmospheric and ... -
Oceanography of the Strait of Sicily: proceedings of a conference held at SACLANTCEN on 11-12 April 1972
(NATO. SACLANTCEN, 1972/09) -
On adaptive modulation for low SNR underwater acoustic communications
(CMRE, 2019/05)This paper deals with adaptive underwater acoustic (UWA) communications where the receiver must operate at low signal-to-noise ratios (SNRs). The proposed modem is equipped with a set of direct sequence spread spectrum ... -
On adaptive underwater object detection
(NURC, 2012/04)A new algorithm for the detection of underwater objects in sonar imagery is proposed. One particularly novel component of the algorithm also detects the presence of, and estimates the orientation of, sand ripples. The ... -
On the applicability of satellite-borne SAR imagery to coastal oceanography
(NATO. SACLANTCEN, 1996/02)Synthetic aperture radar (SAR) images have been acquired from the first European Space Agency (ESA) remote sensing satellite ERS- 1. The mesoscale feature images are from Norwegian coastal waters and the Mediterranean (Elba ... -
On the effects of synthetic-aperture length on SAS seabed segmentation
(NURC, 2009/12)In this work, we quantify the relationship between synthetic-aperture length (or equivalently, along-track resolution) and seabed segmentation performance experimentally for real synthetic aperture sonar (SAS) imagery. The ... -
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 ... -
On the physics and design of electrical discharge sources for active undersea surveillance
(NATO. SACLANTCEN, 1993/08)Underwater electrical arcs have long been used as an impulsive sound source, although efforts to improve efficiency and control acoustic output have been limited by inadequate understanding of the arc initiation process. ... -
On the predictability of subsurface sound speed from satellite-measured sea-surface temperature in the Mediterranean
(NATO. SACLANTCEN, 1996/01)The report investigates the extent to which subsurface sound speed may be determined from satellitemeasured -
On the recording of low frequency signals on magnetic tape
(NATO. SACLANTCEN, 1962/01)A short review of the different methods of recording on magnetic tape is given together with the advantages and disadvantages of each method. Particular emphasis was given to the ability to record low frequencies. This ... -
On the relationship between SAS image resolution and target-detection performance
(CMRE, 2019/06)The relationship between synthetic aperture sonar (SAS) image resolution and target-detection performance is quantified. It is first demonstrated how a lower-resolution SAS system can be simulated in a principled manner ... -
On the spatial variability of the impulse response of an underwater acoustic channel
(NATO. SACLANTCEN, 2000/05)In many applications like adaptive equalization, beam-forming, matched field processing or focalization the performance is limited due to changes in the impulse response caused by variations in source-receiver range or in ... -
On-board real-time assessment of acoustic environmental parameters relevant to the estimation of sonar performance for autonomous underwater vehicles
(CMRE, 2019/05)CMRE is evaluating the use of autonomous robots for the detection and tracking of underwater targets. Robotic detection and localization comes with many challenges, not the least of which is the requirement to maximize the ... -
Online estimation of unknown parameters in multisensor-multitarget tracking: a belief propagation approach
(CMRE, 2019/05)We propose a Bayesian multisensor-multitarget tracking framework, which adapts to randomly changing conditions by continually estimating unknown model parameters along with the target states. The time-evolution of the model ... -
Optimal detection and tracking of acoustical noise sources in a time-varying environment
(NATO. SACLANTCEN, 1982/06)A dynamical detector estimator is derived for nonlinear nongaussian signal processes based on Bucy's representation theorem which is the fundamental result in stochastic filtering. A quantized version of two-dimensional ... -
Optimum bearing resolution for a moving towed array and extension of its physical aperture
(NATO. SACLANTCEN, 1989/04)This report examines the limits of the angular resolution capability of a moving towed array (MTA) by -
Optimum sampling designs for a glider-mooring observing network
(CMRE, 2014/01)Ocean observing systems (OOSs) constituted by moorings and gliders are becoming relevant in oceanographic and climate studies. In these observing networks, the temporal variability is captured by mooring observations, while ... -
An ordered family of consistency measures of belief functions
(CMRE, 2019/05)We propose a family of measures of consistency (and induced conflict) derived from a definition of consistent belief functions introduced previously. Besides satisfying the desired properties of monotonicity, boundedness, ...