Browsing by Title
Now showing items 390-409 of 882
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Horizontal array gain in shallow water
(NATO. SACLANTCEN, 1980/12)Some results of a comprehensive model study on the use of horizontal hydrophone arrays in shallow water are presented. Well-known signal processing techniques are applied to a shallow-water sound propagation model in order ... -
Hybrid Bernoulli filtering for detection and tracking of anomalous path deviations
(CMRE, 2019/05)This paper presents a solution to the problem of sequential joint anomaly detection and tracking of a target subject to switching unknown path deviations. Based on a dynamic model described by Ornstein- Uhlenbeck (OU) ... -
Hydrographic measurements in the southern Iceland and Norwegian Seas during June and August, 1989
(NATO. SACLANTCEN, 1993/12)This memorandum documents an extensive collection of CTD data made during two cruises in the region between Greenland and Norway -
Hydrography of the Iceland-Faeroe Ridge during March 1992: environmental data during NORDIC 92
(NATO. SACLANTCEN, 1992/12)This memorandum documents an extensive collection of CTD and XBT data made on the Iceland-Faeroe Ridge in March, 1992 by the SACLANTCEN vessel Alliance and the FWG vessel Planet as part of a larger operation called NORDIC ... -
Icelandic current experiment GIN Sea Cruise 88 data report: Hydrography and circulation: volume 1
(NATO. SACLANTCEN, 1992/09)The hydrographic and circulation data from the GIN '88 cruise on board the R/V Alliance are summarised in this data report. This cruise constituted the first component of the Icelandic Current Experiment, an observational ... -
Icelandic current experiment GIN Sea Cruise 88 data report: Hydrography and circulation: volume 2
(NATO. SACLANTCEN, 1992/09) -
Identification of sea surface temperature (SST) variability areas through a statistical approach using remote sensing and numerical ocean model data
(CMRE, 2019/06)An understanding of environmental variability (stability/instability) is important to support operational planning of expeditionary warfare and littoral operations, as well as for preparing the Recognized Environmental ... -
The impact of covariance localization on the performance of an ocean EnKF system assimilating glider data in the Ligurian Sea
(CMRE, 2019/05)Data assimilation through an ensemble Kalman filter (EnKF) is not exempt from deficiencies, including the generation of long-range unphysical correlations that degrade its performance. The covariance localization technique ... -
The impact of sea state on HF surface-wave radar ship detection and tracking performances
(CMRE, 2019/06)Nowadays, we face an ever increasing interest in new technologies and solutions for the maritime surveillance (MS) domain. In such a context, oceanographic high-frequency surface-wave (HFSW) radars have started to get ... -
Impact of seafloor and water column parameter variations on signal-to-background ratio estimates: a sensitivity study based on sonar performance modeling
(NURC, 2006/08)Regardless of how accurate modeling can be, if the set of assumptions made with regard to the propagation conditions are not precise, sonar performance predictions diverge from the corresponding measured values. Here a ... -
Impact of uncertain environmental knowledge on the shallow-water transfer function
(NATO. SACLANTCEN, 1992/12)It is assumed that the acoustic channel can be modeled as a linear time-invariant space-variant filter. In this case, from linear systems theory, it is known that the filter output, that is the predicted source signal ... -
Improvements to data networks in support of REA during Generic Oceanographic Array Technology (GOATS) 98
(NATO. SACLANTCEN, 2000/05) -
Impulse response of a layered bottom
(NATO. SACLANTCEN, 1967/01)Numerical methods are used for the Fourier inversion of the frequency-dependent loss transfer function. Because of the non-zero finite values of the integrand for an infinite high frequency, the asymptotic value is subtracted ... -
In-situ acoustic received level measurements with glider based reactive behaviour
(CMRE, 2019/06)Buoyancy-driven underwater gliders are typically employed to sample the water column environment in the ocean [1]. As one of the efforts of extending the capabilities of traditional underwater gliders, CMRE has been working ... -
Incidence du bruit acoustique de thoniers ligneurs et senneurs français sur leurs performances de peche
(NATO. SACLANTCEN, 1985/01)Les auteurs présentents quelques expertises acoustiques provenant de deux études réalisées par le GERBAM: - la première, sur 95 thoniers ligneurs pratiquant la pêche du germon (Thunnus alalunga), -la second, sur 18 thoniers ... -
Incoherent sub-band averaging for improved target detection and Doppler estimation in linearly frequency modulated continuous active sonar
(CMRE, 2019/05)Linear frequency modulated (LFM) continuous active sonar (CAS) waveforms show promise for use in target tracking given that waveforms can be split into sub-waveforms (sub-bands), thereby increasing the target refresh rate. ... -
Increasing the operational safety of autonomous underwater vehicles using the JANUS communication standard
(CMRE, 2019/05)Increasing the operational safety of Autonomous Underwater Vehicles (AUVs) is necessary to fully explore their potential. Currently, AUV operations are limited by several constrains including the need to guarantee no ... -
Influence of background-noise spatial coherence on high-resolution passive method
(NATO. SACLANTCEN, 1982/06)New signal processing methods for passive listening have appeared recently : they are called "high resolution" methods because they have theoretically a better resolving power than conventional or adaptive beamforming . ... -
Influence of internal waves on sound propagation in the SOFAR channel
(NATO. SACLANTCEN, 1975/10)In this paper theoretical investigations due to the influence of internal waves to sound propagation in the SOFAR-channel are presented. The undisturbed acoustic field is described by a normal-mode model. The disturbance ... -
Information and source quality ontology in support of maritime situational awareness
(CMRE, 2019/05)To support situation awareness, the benefit of using a variety of sources is undeniable although it brings additional challenges related to possible conflicting information, heterogeneity in data formats, semantics, ...