Browsing CMRE Publications by Issue Date
Now showing items 381-400 of 882
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Effect of different bandwidths for the detection of extended targets in reverberation
(NATO. SACLANTCEN, 1993/08)In this paper, firstly the theoretical background of bandwidth effects on detection in noise and reverberation is presented in some detail, and secondly the relevant results of sea. trials with a low frequency active sonar ... -
The Response model: an operational model for towed array shape and attitude estimation validated on TABAT data
(NATO. SACLANTCEN, 1993/08)An operational model for array shape and attitude estimation, based on the continuous measurement of heading and depth at a single position in the array, is presented. This model, which we call the Response model has been ... -
Inversion of seismo-acoustic data using genetic algorithms and 'a posteriori' distributions
(NATO. SACLANTCEN, 1993/08)The goal of many underwater acoustic modelling problem is to establish the physical parameters of the environment. With the increase in -
Correlation of backscatter with bottom topography
(NATO. SACLANTCEN, 1993/08)Practical data from low frequency sonar operations in shallow water has been analysed to demonstrate that a high degree of correlation exists between the received signal due to bottom hackscattering and the hottom gradient ... -
Practical active sonar receiver systems using fast frequency-domain correlation
(NATO. SACLANTCEN, 1993/08) -
Real time-frequency active sonar processing: a massively parallel approach
(NATO. SACLANTCEN, 1993/08)A paradigm for massively parallel processing of matched filters, replica correlators, ambiguity functions and time-frequency distributions using an SIMD (Single Instruction Multiple Data) programming methodology is presented. ... -
Environmental impact on mobile sonar shallow water operations
(NATO. SACLANTCEN, 1993/08)Shallow Water operations provide unique challenges for mobile sonars. In many cases propagation conditions can be optimized - our studies have shown that sound channeling can occur in approximately 75% of the strategic ... -
Low frequency resonance backscatter from near-surface bubble clouds
(NATO. SACLANTCEN, 1993/08)When active sonar systems are used to insonate the sea surface, anomalous scattering is observed in the form of enhanced backscatter, and more importantly, in the form of discrete, bright echoes. The most plausible explanation ... -
Low frequency active sonar: a NATO Conference held by SACLANTCEN on 24-28 May 1993 - collection of unclassified papers - volume 2 of 2
(NATO. SACLANTCEN, 1993/08)A conference on Low Frequency Active Sonar was held at SACLANTCEN from 24th to 28th May 1993. The conference was attended by over 100 delegates from NATO countries, and the topics presented ranged from environmental aspects, ... -
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. ... -
Statistical characterization of shallow-water bistatic sonar reverberation and noise
(NATO. SACLANTCEN, 1993/08)Shallow-water, low-frequency bistatic sonar measurements often exhibit high noise caused by bathymetric reverberation and other sources. Understanding the noise statistics is an essential first step in developing filters ... -
About the effective Doppler sensitivity of certain nonlinear chirp signals (NLFM)
(NATO. SACLANTCEN, 1993/08) -
Low frequency active sonar: a NATO Conference held by SACLANTCEN on 24-28 May 1993 - collection of unclassified papers - volume 1 of 2
(NATO. SACLANTCEN, 1993/08)A conference on Low Frequency Active Sonar was held at SACLANTCEN from 24th to 28th May 1993. The conference was attended by over 100 delegates from NATO countries, and the topics presented ranged from environmental aspects, ... -
Considerations related to warfare system design and operation of tactical platforms in a low- frequency active sonar environment
(NATO. SACLANTCEN, 1993/08)Low-Frequency Active Sonar System (LFASS) can provide significant improvements in the detection, localization and classification of very quiet submarine contacts. Achievement of the predicted performance improvements will ... -
Low frequency active sonar noise rejection in a multistatic sonar system
(NATO. SACLANTCEN, 1993/08)The use of low frequency active sonar for ASW has repercussions on automated detection performance. Input data contain not only target returns, but also noise formed by returns from the environment The detector may report ... -
Effects of intrinsic medium inhomogeneities on long-range acoustic transmission
(NATO. SACLANTCEN, 1993/10)Duda et al. [J. Acoust. Soc. Am. 92(2), 939-955, 1992] have measured wavefront arrival times over a -
Robust broadband matched-field processing: performance in shallow water by simulation
(NATO. SACLANTCEN, 1993/11)An issue of concern for matched-field processing is the strong dependence between performance and -
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 -
C-SNAP: Coupled SACLANTCEN Normal mode propagation loss model
(NATO. SACLANTCEN, 1993/12)On the basis of a widely used and efficient range-independent normal mode code, SNAP, and a numerical solution technique for one-way mode coupling obtained from KRAKEN, we have built a range-dependent propagation loss model ... -
Performance assessment of the SACLANTCEN vertical array in shallow water
(NATO. SACLANTCEN, 1994/03)In this memoranduin the performance of the SACLANTCEN vertical