Browsing CMRE Publications by Title
Now showing items 742-761 of 882
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Spectral integral representations of scattering from volume inhomogeneities
(NATO. SACLANTCEN, 1999/07)In-situ measurements of scattering strength can be obtained by analyzing the early-time, high angle reverberation from bottom and sub-bottom features. In order to provide insight into the mechanisms which cause bottom ... -
Statistical characteristics of large-scale bottom reverberation
(NATO. SACLANTCEN, 1995/07)Simulation results from a statistical characterization of large-scale bottom reverberation from broadband signals are presented. The seafloor profile is parametrized via the surface root-mean-square height and correlation ... -
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 ... -
Statistical evaluation of 80 kHz shallow-water seafloor reverberation
(NATO. SACLANTCEN, 1997)In this work a comparison is presented between 80 kHz reverberation statistics obtained at shallow water sites around Sardinia and Sicily. The data include measurements from several distinct bottom provinces, including ... -
Statistical evaluation of 80 kHz shallow-water seafloor reverberation
(NATO. SACLANTCEN, 1997/09)Knowledge of the background reverberation environment is a prerequisite for the design of any target detection scheme. While the problem of understanding and predicting high-frequency background reverberation level or mean ... -
Statistical normalization of non-Rayleigh reverberation
(NATO. SACLANTCEN, 2000/02)Low-frequency active sonar systems operating in shallow water are primarily limited by reverberation. -
Status of ray theory development of Naval Undersea Research and Development Center
(NATO. SACLANTCEN, 1971/12)The first part of this paper discusses NUC (Naval Undersea Research and Development Center) work on the accuracy and validity of ray theory. By comparing the range to convergence zones as indicated by experiment and by ... -
Stochastic methods of sound-field computation
(NATO. SACLANTCEN, 1975/10) -
Studies on information mechanics
(NATO. SACLANTCEN, 1987/04)Related issues connected with the transmission of information in a command and control environment -
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 ... -
Sub-sea floor buried reflectors imaged by low frequency active sonar
(NATO. SACLANTCEN, 1996/06)Low Frequency Active Sonar (LFAS) utilizes low-frequency acoustic -
Subcritical penetration of narrow Gaussian beams into sediments
(NATO. SACLANTCEN, 1988/03)Complete wave-theory solutions have been obtained numerically for both the reflected and the transmitted fields associated with a narrow Gaussian beam incident on a water-sediment interface near the critical grazing angle. ... -
Summary and recommendations
(NATO. SACLANTCEN, 1971/12)An unfortunate first impression might be that ray tracing is dull, simply because the idea is a very old one. In fact, ray tracing is the single most powerful method available to us for understanding the complexities of ... -
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 ... -
SUPREMO: a multistatic sonar performance model
(NATO. SACLANTCEN, 2002/11)Multistatic sonars introduce new problems to the modeller such as mutual interference from multiple sources and variable target aspect in a background of range-dependent bistatic reverberation. A multistatic sonar performance ... -
Surface duct propagation loss measurements and model predictions at low and mid frequencies
(NATO. SACLANTCEN, 1993/08)Side-by-side measurements of low- and mid-frequency propagation loss were obtained during a sea test conducted in the North Atlantic during February of 1992. These measurements are compared to each other and with model ... -
Surface measurements made during the Icelandic Current Experiment (ICE 89) from the R/V Alliance
(NATO. SACLANTCEN, 1991/10)Measurements of surface meteorology and sea temperature taken during the GIN '89A cruise of the research vessel Alliance are presented in the form of time-series plots. The cruise was in the southern Icelandic and Norwegian ... -
Surface measurements made from the R/V ALLIANCE during the Mediterranean aircraft-ship transmission experiment (MASTEX), June 1990
(NATO. SACLANTCEN, 1992/12)Measurements of sea-surface temperature, surface meteorology and atmospheric profiles taken during the June 1990 cruise of the R/V Alliance in the Aegean and Ionian Seas are presented in graphical form. True winds, net ... -
Surface wave spectra
(NATO. SACLANTCEN, 1975/10)A classification is made of the different types of wave elevation spectra namely lD time spectra, lD spatial spectra, 2D spatial spectra and 3D space-time spectra. Relations with simple single parameter measures of surface ... -
Swath bathymetry and SAS autofocus using a Chirp source
(NATO. SACLANTCEN, 1997)Swath bathymetry and SAS autofocus can both be treated as problems in correlating echoes from a scatterer distribution on the seabed. Using a chirp source, the phase derived from quadrature match-filtering can replace the ...