Browsing by Title
Now showing items 491-510 of 882
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Modeling of subcritical penetration into sediments due to interface roughness
(NATO. SACLANTCEN, 1997)Recent experimental results reveal acoustic penetration into sandy sediments at grazing angles below the critical angle. We have been investigating a mechanism for subcritical penetration based on scattering at a rough ... -
Modeling range-dependent, high-frequency, shallow-water torpedo reverberation data
(NATO. SACLANTCEN, 1997)The high-frequency, forward bottom losses predicted by a lossy Rayleigh and a Biot poroelastic sediment model are substantially different. These differences will accumulate and become measurable in multiple bottom bounce ... -
Modeling vessel kinematics using a stochastic mean-reverting process for a long-term prediction
(CMRE, 2019/06)We present a novel method for predicting long-term target states based on mean-reverting stochastic processes. We use the Ornstein-Uhlenbeck (OU) process, leading to a revised target state equation and to a time scaling ... -
Modelling acousto-elastic waveguide/object scattering with the Rayleigh hypothesis
(NATO. SACLANTCEN, 1998/06)In this memorandum the plane wave scattering matrices for a range-dependent seabed and upper free surface are computed using the -
Modelling of scattering by objects on the seabed
(NATO. SACLANTCEN, 1997/12)This paper describes some of the theory and implementation issues of modeling the backscattered -
Modelling of scattering by partially buried elastic cylinders
(NATO. SACLANTCEN, 1998/02)The work of a previous memorandum on the modelling of scattering by a partially buried cylinder is extended to allow the cylinder to have full elasticity (and not just be a fluid structure as in the previous work). The ... -
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. ... -
A modem design for underwater acoustic networking in the High North
(CMRE, 2019/05)We design a software modem for long range underwater acoustic communications in ice-covered oceans. The modem is equipped with three coded modulation schemes achieving 1.8, 21.4 and 96.2 bps, respectively. In addition, we ... -
The Mondrian detection algorithm for sonar imagery
(CMRE, 2019/06)A new algorithm called the Mondrian detector has been developed for object detection in high-frequency synthetic aperture sonar (SAS) imagery. If a second (low) frequency-band image is available, the algorithm can seamlessly ... -
Moving JANUS forward: a look into the future of underwater communications interoperability
(CMRE, 2017/11)In the past 8 years, the Centre for Maritime Research and Experimentation (CMRE) has developed, tested and promoted JANUS - a robust and simple modulation and coding scheme to be used as the first standard to support ... -
Multi-criteria weather routing optimization based on ship navigation resistance, risk and travel time
(CMRE, 2019/05)This paper presents the analysis of the weather routing scenario in a multi-criteria setup. The set of 3 conflicting criteria is: added navigation resistance (caused by wind and waves), navigation risk and travel time. To ... -
Multi-domain robotics competitions: the CMRE experience from SAUC-E to the European Robotics League Emergency Robots
(CMRE, 2019/06)This paper details the experience of the Centre for Maritime Research and Experimentation (CMRE) in the organisation of several robotics competitions since 2010. In particular, the Student Autonomous Underwater Vehicle ... -
Multi-look processing of high-resolution SAS data for improved target detection performance
(CMRE, 2019/06)The rich content of synthetic aperture sonar (SAS) data is typically used to generate imagery with resolution as high as theoretically possible. But when the ultimate purpose of the imagery is for detecting objects with ... -
Multi-sensor data acquisition, tracking, fusion and intelligent decision aids in the NATO Maritime Situational Awareness Initiative: countering underwater intruders
(NURC, 2007/10)The objective of the NATO Maritime -
Multi-sensor ISAR technique for translational motion estimation
(CMRE, 2019/06)In the last years a lot of interest has grown concerning the exploitation of data acquired by multiple sensors belonging to multistatic or Multiple Input Multiple Output systems. Indeed increased information and/or better ... -
Multi-view SAS image classification using deep learning
(CMRE, 2017/11)A new approach is proposed for multi-view classification when sonar data is in the form of imagery and each object has been viewed an arbitrary number of times. An image-fusion technique is employed in conjunction with a ... -
Multi-view target classification in synthetic aperture sonar imagery
(NURC, 2009/12)This work proposes an elegantly simple solution to the general task of classifying the shape of an object that has been viewed multiple times. Specifically, this problem is addressed in the context of underwater mine ... -
Multi-waveform active sonar tracking
(NURC, 2007/06)This paper extends the NURC distributed multihypothesis -
Multipath field representation for seabed parameter extraction using backscatter data from shadow zones
(NATO. SACLANTCEN, 1997)Inversion strategies for bottom parameter estimation in shallow water impose stringent requirements on accuracy and speed of acoustic models. We highlight the importance of second order effects as first order determinants ... -
Multipath pulse shape in a refracting environment
(NURC, 2007/11)Multiple boundary interactions in shallow water propagation introduce a more or less Gaussian angle distribution at a distant receiver. When all paths are added the result is 'mode-stripping', i.e. the steep rays are ...