Browsing Reprints by Title
Now showing items 150-169 of 548
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Correlation of backscatter with bottom topography
(NATO. SACLANTCEN, 1993/08)Practical data from low frequency sonar operations in shallow water has been analysed to demonstrate that a high degree of correlation exists between the received signal due to bottom hackscattering and the hottom gradient ... -
Counter piracy surveillance requirements for early detection, military rescue, or evasion
(NURC, 2012/06)Best practice for protection against pirates includes coordination with the military forces operating in the area, constant watch against the approach of pirates, and measures to prevent or delay their boarding. The time ... -
Critical angle and seabed scattering issues for active-sonar performance predictions in shallow water
(NATO. SACLANTCEN, 1997)Active sonar performance predictions (0.75 to 3 kHz) are examined in summer shallow-water environments to quantify the impact of variable seabed and watermass properties on detection. Scattering is computed with an ... -
Current regulatory issues in the usage of autonomous underwater vehicles
(CMRE, 2019/05)Autonomous Surface Vehicles (ASVs) are becoming increasingly popular for a large number of applications from oceanography to border protection and shipping. In particular, the advent of long-term ASVs allows for months-long ... -
Data driven vessel trajectory forecasting using stochastic generative models
(2019/05)In this work, we propose a data driven trajectory forecasting algorithm that utilizes both recorded historical and streaming trajectory observations. The algorithm performs Bayesian inference on a directed graph the walks ... -
Data-driven detection and context-based classification of maritime anomalies
(CMRE, 2019/06)Discovering anomalies at sea is one of the critical tasks of Maritime Situational Awareness (MSA) activities and an important enabler for maritime security operations. This paper proposes a data-driven approach to anomaly ... -
Decision tree-based adaptive modulation for underwater acoustic communications
(CMRE, 2017/11)Underwater acoustic channels are characterised by non-stationary fading statistics and consequently, a modulation scheme optimally designed for a specific fading model will underperform when the channel statistics ... -
Demystifying deep convolutional neural networks for sonar image classification
(CMRE, 2019/06)Deep convolutional neural networks (CNNs) are developed to perform underwater target classification in synthetic aperture sonar (SAS) imagery. The deep networks are trained using a huge database of sonar data collected at ... -
Deployment of a persistent underwater acoustic sensor network: the CommsNet17 experience
(CMRE, 2019/05)This paper presents the experimental activities performed by the NATO STO Centre for Maritime Research and Experimentation (CMRE) during the CommsNet17 trial where a persistent Underwater Acoustic Sensor Network (UASN) was ... -
Depth dependence of directionality of ambient noise in the North Pacific: experimental data and equipment design
(NATO. SACLANTCEN, 1982/06)Ambient ocean noise studies have been part of the research program of the Marine Physical Lab (MPL) for many years. In recent years this work has included several studies of the depth dependence of vertical directionality ... -
Design of synthetic aperture sonar systems for high-resolution seabed imaging (tutorial slides)
(NURC, 2006/10)This tutorial reviews the key aspects of the design of synthetic aperture sonar (SAS) systems for -
Detecting anomalous deviations from standard maritime routes using the Ornstein-Uhlenbeck process
(CMRE, 2019/05)A novel anomaly detection procedure based on the Ornstein-Uhlenbeck (OU) mean-reverting stochastic process is presented. The considered anomaly is a vessel that deviates from a planned route, changing its nominal velocity ... -
Detection models and target information processing
(NATO. SACLANTCEN, 1982/06)The passive sonar equation leads in a natural manner to sensor detection performance contours. Useful information can be extracted from observed fractional holding time on non-cooperative targets by use of these contours. ... -
Detection rate statistics in synthetic aperture sonar images
(NURC, 2009/12)Synthetic aperture sonar (SAS) has proved to be successful for mine hunting andis now robust for generating high-resolution images over wide swath. The subsequent stepin the processing is detection, discriminating between ... -
Detection, tracking and fusion of multiple HFSW radars for ship traffic surveillance: experimental performance assessment
(CMRE, 2014/05)Low-power HF surface-wave radars fit well the role of long-range early-warning tools in maritime situational awareness applications, by virtue of their over-the-horizon coverage capability and continuoustime mode of ... -
Determination of velocity profile and sea bed characteristics from high frequency pulse propagation in a shallow water Mediterranean environment
(NATO. SACLANTCEN, 1997)Time-domain features of shallow water Mediterranean and Yellow Sea data are simulated for frequency band widths of 0.8 kHz with a centralfrequency of 3.2 kHz. Contour plots of pulse arrivals in time and depth are analyzed ... -
Deterministic methods of sound field computation
(NATO. SACLANTCEN, 1975/10)Models for acoustic propagation in the ocean environment have matured to a level where they are used routinely to estimate deterministic phenomena and, most recently, have been applied to the investigation of stochastic ... -
Deterministic propagation modelling: Part 1: Fundamental principles *Part 2: Numerical results
(NATO. SACLANTCEN, 1981/06)The physics of sound propagation in the ocean is briefly reviewed. The wave equation is presented and a set of solutions under a variety of approximations is discussed. The consistency among these solutions is illustrated. -
Development of a software-defined and cognitive communications architecture at CMRE
(2019/05)This paper presents an overview of the functionalities of the Cognitive Communications Architecture (CCA) that is currently under development at the NATO Science and Technology Organisation (STO) Centre for Maritime Research ...