Browsing CMRE Publications by Title
Now showing items 200-219 of 882
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Bottom reverberation in shallow water: coherent properties as a function of bandwidth, waveguide characteristics and scatterer distribution
(NATO. SACLANTCEN, 1998/10)Scattering physics are often modeled using the Helmholtz equation for computational reasons. Likewise, propagation loss to and from scattering regions are often treated in a like manner. The usual approach for generating ... -
Bottom scattering measurements in shallow water
(NATO. SACLANTCEN, 1999/08)Sonar performance predictions of reverberation in shallow water rely upon good estimates of the bottom scattering strength. However, little is understood about bottom scattering in shallow water in -
Bottom time spread and bistatic scattering by rough basalt
(NATO. SACLANTCEN, 1993/08)Scattering from oceanic basalt affects low-frequency active sonar systems in at least two important ways: (1) Significant time, angle and frequency spreading reduces target echo levels when systems over-resolve the spread; ... -
Bottom-interacting ocean acoustics: proceedings of a conference held at SACLANTCEN on 9-13 June 1980
(NATO. SACLANTCEN, 1980/07) -
Bottom/subbottom surveying using a new, parametric, sidescan sonar
(NATO. SACLANTCEN, 1997)The Naval Research Laboratory (NRL) has developed a dual-frequency, towed, interferometric, sidescan sonar system known as the Subbottom Swath System, which is capable of detecting objects and structures buried below the ... -
Broad-band geoacoustic inversion in shallow water from waveguide response measurements on a single hydrophone: theory and YELLOW SHARK experimental results
(NATO. SACLANTCEN, 1999/05)Executive summary: Performance models such as the Allied Environmental Support System (AESS) require environmental input parameters such as the geoacoustic properties of the battlespace. The models ingest the input parameters ... -
Broadband acoustic transmission intensity fluctuations in the Tyrrhenian Sea
(NATO. SACLANTCEN, 1996/11)An acoustic propagation experiment was carried out in the Tyrrhenian Sea in October 1985 in which signals from a broadband source were recorded at a range of 5 km with a vertical 62 m hydrophone array over a period of 5 ... -
Broadband geo-acoustic inversion from sparse data using genetic algorithms: results from the 1997 Geo-Acoustic Inversion Workshop
(NATO. SACLANTCEN, 1998/03)Matched field acoustic inversion techniques were investigated -
Broadband signal simulation in shallow water
(NATO. SACLANTCEN, 2002/12)Today's minimum requirements for ocean acoustic models are to be able to simulate broadband signal transmissions in 2D varying environments with an acceptable computational effort. Standard -
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 ... -
Calculation of propagation losses in a medium with a velocity profile approximated by a number of Epstein profiles
(NATO. SACLANTCEN, 1971/12)This paper presents a digital ray-theory program, by which the ray trace, travel time and intensity can be calculated for velocity profiles approximated by a number of Epstein functions. -
Calculation of reverberation and average intensity of broadband acoustic signals in the ocean by means of the RAIBAC computer model
(NATO. SACLANTCEN, 1976/04)Based on the conventional ray-tracing principle, a fast numerical algorithm is developed that calculates averaged propagation loss and reverberation of underwater sound. The averaging is performed by summing incoherently ... -
Camelot - localization beacon system
(CMRE, 2019-05)C2 Advanced Multi-Domain Environment And Live Observation Technologies (CAMELOT) is a H2020 project intended to develop and demonstrate different advanced command and control service modules for multiple platform domains ... -
Cardioid receive array calibration for active systems
(NURC, 2006/08)Nowadays active detection improvement relies significantly on advanced sensor technology, such as the cardioid receive array that allows the directional (right/left) discrimination of the received signal. However, in ... -
Celtic Duet - a joint SACLANTCEN/NRL shallow-water sea trial in Celtic Sea during July 1992: data summary
(NATO. SACLANTCEN, 1996/10)In July 1992 a joint shallow-water sea trial was conducted in the -
Channel sensitive processor: real data processing
(NATO. SACLANTCEN, 1998/02)The CSP is applied to data collected during the DUSS97 sea trial. A one-way geometry is used and the transmitted signal propagation time is known a priori. As predicted by analytical and simulation studies, the CSP detector ... -
Channel sensitive processor: sensitivity and optimization study
(NATO. SACLANTCEN, 1997/10)The detection performance of the Channel-Sensitive Processor (CSP) has been tested in dense multipath conditions. It was demonstrated that, for a known propagation channel, the CSP outperforms the conventional matched ... -
Channel-adapted source for shallow water
(NATO. SACLANTCEN, 1993/08)In shallow water areas the utilization of active sonar is complicated by the fact that in these environments the performance of active systems is degraded by source signal interaction with channel boundaries. These boundary ... -
Channel-sensitive processor: development and detection performance evaluation
(NATO. SACLANTCEN, 1997/03)A Channel Sensitive Processor (CSP) which improves upon the detection performance of the traditional matched filter is developed. This method compensates for the performance degradation of the matched filter due to dense ... -
Characteristics of the mediterranean seagrass Posidonia oceanica contributing to high-frequency acoustic scattering
(NATO. SACLANTCEN, 2000/05)Posidonia oceanica meadows are the most important ecosystem for the life cycle of coastal Mediterranean benthos with a fundamental role in the primary production of the neritic system and a decisive influence on other ...