Browsing Technical Reports by Issue Date
Now showing items 101-120 of 322
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Results on the detection of narrow-band low-level signals in a ship-induced noise field using high-resolution beamforming
(NATO. SACLANTCEN, 1988/07)In this report the performance of a high-resolution beamformer is compared to that of the conventional -
Estimators for model-based passive localization
(NATO. SACLANTCEN, 1988/07)A comparative study is made of the performance of four different estimators as used in the matched field technique of passive localization. The study is based on both real and synthesized data. In the synthesized data case, ... -
Acoustic source-level measurements for a variety of merchant ships
(NATO. SACLANTCEN, 1988/07)This report describes a set of 50 source spectra obtained from merchant ships of opportunity near Genova, Italy. These spectra were obtained from radiated-noise spectra measured on a towed array and a transmission-loss ... -
Detection of narrow-band low-level signals: simulated performance of high-resolution eigenstructure methods versus conventional beamforming
(NATO. SACLANTCEN, 1988/08)In this report the detection of narrow-band low-level signals by passive sonar is addressed, -
Deconvolution by homomorphic and Wiener filtering
(NATO. SACLANTCEN, 1988/09)This study is concerned with deconvolution methods applied to underwater propagation in shallow -
SAFARI Seismo-Acoustic Fast field Algorithm for Range-Independent environments: user's guide
(NATO. SACLANTCEN, 1988/09)An efficient algorithm has been developed for solving the depth-separated wave equation in general fluid/solid horizontlly stratified media. The algorithm has been built into a general-purpose package of computer codes ... -
Mixed layer deepening and variability in the upperlayers if the central western Mediterranean, MILEX-82: final report
(NATO. SACLANTCEN, 1988/10)The 1982 Mixed-Layer Experiment (MILEX-82) is described in detail and the data are presented in ways designed to illustrate the spatial and temporal variability of the surface and deeper layers of the central western ... -
Extended towed-array processor by overlapped correlator
(NATO. SACLANTCEN, 1988/11)The development of an algorithm for extended towed-array measurements, which could be used by matched-field estimators to obtain information about depth and range of a source, is studied. This algorithm combines coherently ... -
An autonomous undersea surveillance vehicle: concept and operational feasibility
(NATO. SACLANTCEN, 1988/12)The concept of autonomous undersea vehicles (AUVs) is becoming feasible through the increasing practicality of artificial intelligence, decreasing size and cost of computers, and improved technical capabilities. This paper ... -
Test and evaluation of objective mapping applied to oceanographic data from GIN Sea'86
(NATO. SACLANTCEN, 1989/03)This study is an investigation to produce an objective analysis -
Sediment shear waves: a comparison of in situ and laboratory measurements
(NATO. SACLANTCEN, 1989/03)Surficial sediment shear wave velocity measurements were made at eight sites (water depths 7-22 m) -
A note on attenuation and dispersion in marine sediments
(NATO. SACLANTCEN, 1989/04)From the more recent investigations reported ill the literature, -
Delay-Doppler resolution performance of large time-bandwidth product linear FM signals in a multi- path ocean environment
(NATO. SACLANTCEN, 1989/04)Active sonar systems that transmit large time-bandwidth (TW)-product linear frequency modulated (LFM) waveforms and receive echoes from targets of unknow~r~an ge and speed can suffer considerable correlation losses that ... -
Optimum bearing resolution for a moving towed array and extension of its physical aperture
(NATO. SACLANTCEN, 1989/04)This report examines the limits of the angular resolution capability of a moving towed array (MTA) by -
The effect of thermohaline variability on the exchange through Mediterranean straits
(NATO. SACLANTCEN, 1989/05)exchanges through straits. The primary assumption is that the exchange is determined by tlle pressure force created by the differing weights of tlle water columns on either side of the sill and by the continuity of mass ... -
Acoustic bottom reflectivity
(NATO. SACLANTCEN, 1989/06)Acoustic reflectivity from the seafloor is often an important factor influencing the performance of ASW systems in different environments, such as in deep water when the bottom bounce paths are used, and in general in ... -
Transmission-time variability, vertical spatial and temporal analysis of NAPOLI'85, an experiment in the Tyrrhenian Sea
(NATO. SACLANTCEN, 1989/09)An acoustic propagation experiment (NAPOLI '85) 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 ... -
Assimilation of hydrographic data from the Atlantic inflow experiment into ocean models
(NATO. SACLANTCEN, 1989/10)This study represents the link between observational and numerical programs. A method for data -
Pre-design operational requirements for underwater drones
(NATO. SACLANTCEN, 1989/11)The purpose of this report, prepared at the behest of Panel 7 of the Defence Research Group at NATO headquarters in Brussels, is to list -
Upper layer environmental parameters from CTD data - GIN '86 cruise
(NATO. SACLANTCEN, 1989/12)The data from the SACLANTCEN June 1986 Cruise is analysed