Browsing Technical Reports by Type "Scientific Memorandum (SM)"
Now showing items 1-20 of 159
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A collection of analytical results related to the ASW protection of convoys and carriers
(NATO. SACLANTCEN, 1987/07)This paper is a collection of diverse analytical results that are related to several aspects of a common problem: the defence of carriers against torpedo-firing submarines. This work is not in any sense a complete treatment ... -
A method for determining absolute velocities from hydrographic data: the numerical code
(NATO. SACLANTCEN, 1988/02)The numerical procedure associated with the inverse method of Peggion (1987) is described. The model equations are formulated on a spherical-shell coordinate system. The method is applied to a limited area of the basin of ... -
A method for the three-dimensional reconstruction of underwater objects
(NATO. SACLANTCEN, 1996/10)This report describes a method to estimate the three-dimensional aspects of underwater objects using a sequence of sonar images. The data are recorded by a sector scanning sonar, carried by an underwater vehicle which ... -
A method to quantify shortfalls and cost benefits for the MO 2015 ASW advanced concepts study
(NATO. SACLANTCEN, 1997/06)An ASW Advanced Concepts Study (ACS) has been initiated as part of Phase 2 of NATO Study, "Implications of New Technology for Maritime Operations in 2015". In this paper, a method to assess ASW search operations is described ... -
A microcomputer-controlled digital acquisition and analysis system for the expendable bathythermograph
(NATO. SACLANTCEN, 1985/10)For a number of years the expendable bathythermograph (XBT) has been an important tool for basic and applied oceanographic survey work. This has led to a significant body of work being done on the accuracy of the XBT system ... -
A note on attenuation and dispersion in marine sediments
(NATO. SACLANTCEN, 1989/04)From the more recent investigations reported ill the literature, -
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 ... -
A review of the application of UUV technology to mine countermeasures
(NATO. SACLANTCEN, 1999/03)The emphasis on littoral warfare, the proliferation of low cost mines available to potentially hostile countries, high exercise costs and risks related to the operation of present NATO MCM units, require the development ... -
A satellite based ocean forecasting system to support naval operations in crisis situations
(NATO. SACLANTCEN, 2000/05)We employ a nonlinear ocean forecasting technique based on a combination of genetic algorithms and empirical orthogonal function (EOF) analysis. The method is used to forecast the space-time variability of the sea surface ... -
A simple deconvolution method for NAPOLI'85
(NATO. SACLANTCEN, 1991/10)An inverse filter (deconvolution in the frequency domain) is applied -
A study of the uncertainty in estimate seabed properties as a result of goeacoustic inversion algorithms
(NATO. SACLANTCEN, 2003/10)This paper investigates the inherent uncertainty in estimated seabed properties derived from matched-field geoacoustic inversion algorithms. This algorithm-induced uncertainty must be considered when interpreting inversion ... -
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 ... -
Accuracy of synthetic aperture sonar micronavigation using a displaced phase centre antenna
(NATO. SACLANTCEN, 1999/02)This work evaluates the accuracy of multi-element synthetic aperture sonar (SAS) micronavigation based on the concept of displaced phase centre antenna (DPCA). The Cramér-Rao lower bound (CRLB) for the joint estimation of ... -
Acoustic impact of upper ocean models
(NATO. SACLANTCEN, 1989/12)The upper mixed-surface layer of the ocean, with its homogeneous vertical temperature profile, provides a somewhat special acoustic propagation environment where the sound speed will increase (due to pressure) down to the ... -
Acoustic models at SACLANTCEN
(NATO. SACLANTCEN, 1995/03)The Environmental Modelling Group at SACLANTCEN maintains a suite of computer codes to model sound propagation in the ocean. This suite contains numerical models to cover all environmental conditions and acoustic frequencies ... -
An analytical study of source localization in shallow water by matched-field processing of horizontal arrays
(NATO. SACLANTCEN, 1992/08)Over the last few years a large number of studies have reported results of range-depth localization of sound sources by matched-field processing of vertical arrays in known environments. The performance of matched-field ... -
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 ... -
An experimental study in forming a long synthetic aperture in the sea
(NATO. SACLANTCEN, 1992/09)Successful experimental testing of synthetic aperture techniques for sonar systems have been very limited and only few results, including very stable CW signals, have been published. These experimental results and theoretical ... -
Analysis of a signal starting time estimator based on the Page test statistic
(NATO. SACLANTCEN, 1995/12)The time of the most recent reset to zero of the Page test statistic is proposed as an estimator of the starting time of a signal. The probability mass function of the estimator is determined analytically subject to a ... -
Analysis of basin backscattering in the Levantine Sea
(NATO. SACLANTCEN, 1989/12)Research has been conducted in the Levantine Sea basin to measure low-frequency basin reverberation and relate the measurements to backscattering strength. The receivers were a towed horizontal array and a suspended vertical ...
