CMRE Open Library: Recent submissions
Now showing items 501-520 of 882
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A towed CTD chain for two-dimensional high resolution hydrography
(NATO. SACLANTCEN, 1997/04)The need for accurate two-dimensional datasets of temperature and salinity in the upper ocean led to the development of a new type of towed chain. Low-cost sensors are moulded in fins and may be randomly placed on the tow ... -
Processing of broadband acoustic signals
(NATO. SACLANTCEN, 1972/05) -
Time-evolution modelling of seafloor scatter: Part 1: Theory
(NATO. SACLANTCEN, 1997/04)A time-series model for acoustic seafloor backscattering is described. -
Toeplitz constrained adaptive beamforming with auxiliary data
(NATO. SACLANTCEN, 1997/02)Submarine and mine detection using active sonar face similar problems when adaptive beamforming is required to provide high angular resolution or to suppress angularly isolated interferences. Both -
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 ... -
Coupled-mode modelling of acoustic scattering from three-dimensional, axisymmetric objects
(NATO. SACLANTCEN, 1997/01)In this memorandum a coupled-mode method for computing the wavefield scattered by three-dimensional, axisymmetric objects is presented. The method provides a unified approach to solving three-dimensional scattering problems ... -
Scattering by spheres buried in sediment
(NATO. SACLANTCEN, 1997/01)In this report the scattering of acoustic energy by an elastic sphere buried in sediment is examined. The geoacoustic model consists of two homogeneous fluid halfspaces separated by an intermediate layer. The source field ... -
Modelling scattering from partially buried cylinders = Acoustic scattering from cylindrical objects embedded between two half-spaces/The computation of the scattered pressure field from a cylinder embedded between two half-spaces = The computation of the scattered pressure field from a cylinder embedded between two half-spaces with different densities
(NATO. SACLANTCEN, 1996/12)1. A boundary integral equation method is presented for the computation of the acoustic field scattered from a cylindrical object which is totally within the water column, totally buried in sediment, or partially buried. ... -
Active signal detection in shallow water using the Page test
(NATO. SACLANTCEN, 1996/11)The use of active sonar in shallow water results in received echoes that may be considerably spread in time compared to the transmitted wave form. The duration and structure of the spreading and the time of occurrence of ... -
Parameter estimation using multi-frequency range-dependent acoustic data in shallow water
(NATO. SACLANTCEN, 1996/11)The estimation of all forward model parameters - geometric, geoacoustic, -
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 ... -
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 -
The joint SACLANTCEN/USA towed vertically directive source - TVDS
(NATO. SACLANTCEN, 1996/07)This report is the text of a paper presented at Undersea Defence Technology, Cannes, 1995 (UDT 95). It outlines the development of the Towed Vertically Directive Source (TVDS) and the associated ship-handling and winching ... -
Tactical data acquisition experiences
(NATO. SACLANTCEN, 1972/05)The requirements of Tactical Data Acquisition systems are discussed and summarized. Experiences with equipment and their utilization are described including : quantities measured, input signal conditioning, analogue ... -
A plane-wave decomposition method for modeling scattering from objects and bathymetry in a waveguide
(NATO. SACLANTCEN, 1996/11)In this paper a straightforward plane-wave decomposition method which can be used for solving object andlor interface scattering problems in a waveguide is described. The method utilizes the free-space scattering matrix ... -
Source localization in shallow water using multi-frequency processing of shot data
(NATO. SACLANTCEN, 1996/07)Multi-frequency processing methods are applied to real data generated by explosives to examine the -
Geoacoustic models for selected shallow water areas
(NATO. SACLANTCEN, 1996/07)This report summarizes recent work on characterization of shallow water -
Planning tools for maritime operations
(NATO. SACLANTCEN, 1996/06)The Commander Allied Naval Forces Southern Europe (COMNAVSOUTH) tasked SACLANT Undersea Research Centre to conduct a study to optimize the employment of limited ASW assets in the protection of shipping in the Western ... -
Finite difference modelling of scattering by objects in the seabed
(NATO. SACLANTCEN, 1996/07)In this report we describe the theory and some implementation issues of a finite difference code used at SACLANT Centre. In particular, we consider the modelling of attenuation and the excitation of a remote incident field ... -
Sub-sea floor buried reflectors imaged by low frequency active sonar
(NATO. SACLANTCEN, 1996/06)Low Frequency Active Sonar (LFAS) utilizes low-frequency acoustic