Browsing Technical Reports by Title
Now showing items 65-84 of 322
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Bathymetric imaging with wideband interferometric synthetic aperture sonar
(NATO. SACLANTCEN, 2001/11)A new approach to interferometric sonar is presented, based on time delay estimation using shortterm correlation of the seafloor backscatter. It is most suited to signals with large relative bandwidths and long interferometric ... -
Benchmarking of SCARAB volume scattering versus OASES volume scattering
(NATO. SACLANTCEN, 2001/05)OASES uses wavenumber integration to solve for the backscattered pressure caused by sound speed and density inhomogeneity scatterers in the sediment; SCARAB uses a ray path technique to find the backscattered intensity. ... -
Benchmarking scattering in ocean waveguides
(NATO. SACLANTCEN, 1995/07)Accurate numerical solutions are presented for benchmark problems -
Bibliography electromagnetic phenomena with special reference to ELF (1-300 cps)
(NATO. SACLANTCEN, 1964/10)Contents: Propagation of EM Waves, Surface Waves, Ionosphere; Calculation of DC and EM Fields, Antennas; Analysis, Measuring Methods, Magnetometers, Correlation; Geomagnetic Fluctuations, Solar Activity, Earth Currents; ... -
Bispectrum of ship-radiated noise
(NATO. SACLANTCEN, 1988/07)The bispectrum of ship radiated noise is estimated. The noise was received on a towed array being towed by the same ship that served as the noise source. The array was beamformed such that the forward endfire beam pointed ... -
Bottom reflection properties deduced from an ambient noise: simulation of a processing technique
(NATO. SACLANTCEN, 2002/11)A promising new method has already been proposed [SACLANTCEN SM-387] to calculate bottom reflection loss from ambient noise directionality. Although this method has been tried experimentally at more than 11 sites under ... -
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-interacting ocean acoustics: proceedings of a conference held at SACLANTCEN on 9-13 June 1980
(NATO. SACLANTCEN, 1980/07) -
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 ... -
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-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 ... -
Comparative calibration programme within NATO countries
(NATO. SACLANTCEN, 1963/11)A NATO inter-laboratory programme of comparative hydrophone calibration is described including a description of the calibration facilities and methods of the participants. Hydrophones Type H29, F31, and F36 from the US ...