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Formal Reports

Report of results of completed projects or major milestones either in scientific terms or in terms acceptable to a wider audience. Note: Unless linked to the full text, reports are only available to NATO member nations from designated distribution centres. 

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An alternative derivation of the scattering matrix under Kirchhoff approximation in electromagnetics An alternative derivation of the scattering matrix under Kirchhoff approximation in electromagnetics

Date added: 02/07/2018
Date modified: 02/07/2018
Filesize: Unknown

An alternative derivation of the scattering matrix under Kirchhoff approximation in electromagnetics. Fuscaldo, Walter; Di Simone, Alessio; Millefiori, Leonardo; Iodice, Antonio; Braca, Paolo; Willett, Peter K.. CMRE-FR-2018-001. January 2018.

This report furnishes an alternative theoretical framework for the analytical evaluation of the bistatic scattering coefficients, under the Kirchhoff approximation (KA) in electromagnetics. Starting from the KA, specific results under the geometrical optics and physical optics approximations are furnished, along with the backscattering geometry. Comparison with classical results available in the related literature validates the proposed derivation. The main objectives of this report are 1) to provide an explicit formulation of the scattering matrix under KA in terms of the incident and scattered unit wavevectors; 2) to provide a more generic derivation of the scattering matrix under the physical optics approximation by relaxing typical hypotheses regarding the geometry of the scattering problem; 3) to highlight some important symmetries of the scattering matrix under KA. The framework proposed here can be exploited to simplify the evaluation of the electromagnetic scattered fields in complex scenarios where multiple-bounce contributions come into play. Indeed, un-der the KA, it is shown that the scattering matrix can conveniently be expressed in terms of few variables, thus greatly reducing the complexity of the theoretical derivation of the scattering matrix.

 

Coded modulation development for covert underwater acoustic communications Coded modulation development for covert underwater acoustic communications

Date added: 01/19/2018
Date modified: 01/19/2018
Filesize: Unknown

Coded modulation development for covert underwater acoustic communications. Pelekanakis, Konstantinos. CMRE-FR-2017-004. December 2017.

This report is an initial study on covert Underwater Acoustic (UWA) communications at the physical layer. The challenge in any covert system design is to operate in very low Signal-to-Noise Ratio (SNR) as well as to cope with the unique factors of UWA channels such as distance-dependent bandwidth due to absorption, long reverberation time due to slow speed of sound (about 1500 m/s) and rapid phase variations due to Doppler effects. Our research focuses on the design of a system for Low Probability of Detection (LPD)/Low Probability of Exploitation (LPE)/Low Probability of Intercept (LPI) communications. The transmitter is based on Direct Sequence Spread Spectrum (DSSS) modulation of Trellis-coded Modulation (TCM) signals and the receiver combines adaptive equalisation with carrier-phase synchronization. A preliminary analysis of signals recorded in a shallow water environment off the coast of Portugal is presented.

NATO Coalition Warrior Interoperability exploration, experimentation, examination, exercise (CWIX) 2017: exercise plan for the NATO-CMRE-GliderC2 capability participation NATO Coalition Warrior Interoperability exploration, experimentation, examination, exercise (CWIX) 2017: exercise plan for the NATO-CMRE-GliderC2 capability participation

Date added: 08/11/2017
Date modified: 08/11/2017
Filesize: Unknown

NATO Coalition Warrior Interoperability exploration, experimentation, examination, exercise (CWIX) 2017: exercise plan for the NATO-CMRE-GliderC2 capability participation. Vicen Bueno, Raul; Cimino, Giampaolo; Cecchi, Daniele; Merani, Diego; Soto, José; Berni, Alessandro. CMRE-FR-2017-001. April 2017.

This report describes the Exercise Plan for CMRE participating in the NATO Exercise CWIX 2017 (Coalition Warrior Interoperability eXploration, eXperimentation, eXamination, eXercise). CMRE will participate with its scientific capability GliderC2 (Underwater Glider Command and Control). This capability is a framework being able to provide live observations from the sea by using unmanned vehicles. Live NU observations acquired by underwater gliders participating in the CMRE scientific sea-trial NREP17 (Nordic Recognized Environmental Picture 2017) will be provided at NS level. NU glider positions/contacts and intended tracks will be provided to C2, Common Operational Picture (COP), Joint Intelligence, Surveillance and Reconnaissance (JISR) and Geospatial, Meteorological and Oceanographic (GEOMETOC) capabilities in near real-time. Forecasts of oceanographic variables (e.g. water temperature, salinity) with glider observation assimilation will be provided as well. Information will be provided through robust and interoperable standards and web-services, which allows CMRE automating the process of information provision to NATO and national capabilities. The main challenge for CMRE in CWIX 2017 will be the remote C2 of live unmanned robots (underwater gliders) from operational commands/sites, such as the NATO Joint Force Training Centre (JFTC) in Bydgoszcz, Poland, where CWIX takes place. This is the first time ever this happens in this NATO exercise. Final users, such as commanders, operators, could have the change to C2 unmanned underwater robots operating at 2,500+ km of distance from JFTC in near real-time at NU level. Mission requirements will be acquired by a web-service running at NS level. The collected information will be automatically provided in near real-time to C2, COP, JISR and GEOMETOC capabilities at NS level using interoperable standards for web-services. Another important challenge for CMRE participation in CWIX 2017 is the virtualization of the NATO-CMRE-GldierC2 capability. This is aligned with the NATO policy on efficiency and efficacy on capability deployment in exercises and operations. This is another step forward operationalization of this capability. CMRE will be contributing into the NATO Recognized Environmental Picture (REP) and Recognized Maritime Picture (RMP) concepts being tested in CWIX 2017. Live observations from the gliders and forecasts of oceanographic variables for the REP, and live positions/contacts and intended tracks of the gliders from the underwater domain for the RMP will be provided. CMRE will be the unique provider of such information in both concepts.

Multi-sensor extended target tracking Multi-sensor extended target tracking

Date added: 06/23/2017
Date modified: 06/23/2017
Filesize: Unknown

Multi-sensor extended target tracking.Vivone, Gemine; Braca, Paolo. CMRE-FR-2017-002. June 2017.

In this report, the multiple sensor extended target tracking problem is studied into the random matrix framework. We deal with data from a network of multiple sensors and focus on the spatial density modelling. The multiple sensor extension for extended target tracking is not straightforward. Indeed, the extent of the target differs when it is observed from different perspectives. The scope of this report is limited by the assumption that there are no clutter measurements and there is exactly one target present in the surveillance area. Four different multi-sensor measurement updates are presented; three updates based on a parametric density representation of the extended target state distribution, and one update based on a Rao-Blackwellized (RB) particle representation of the extended target state distribution. The updates are evaluated and compared in an extensive simulation study using two kinds of simulators evaluating the performance varying the numbers of particles, the numbers of detections per target, the numbers of sensors, and the noise levels. Results show that the RB particle filter gives the best performance, at the price of higher computational cost.

A risk game formalization in support to maritime situation awareness automation: analysis of reasoning profiles A risk game formalization in support to maritime situation awareness automation: analysis of reasoning profiles

Date added: 03/08/2017
Date modified: 03/08/2017
Filesize: Unknown

A risk game formalization in support to maritime situation awareness automation: analysis of reasoning profiles. Jousselme, Anne-Laure; Ben Abdallah, Nadia; Pichon, Fréderic. CMRE-FR-2016-011. December 2016.

This document follows on previous work on the Risk Game, a general methodology developed at CMRE to elicit experts knowledge and know-how, and their ability to deal with information of different nature, to consider the information quality and to reason about concurrent events. It is a contrived technique aimed at capturing data expressing human reasoning features while performing a specific task of maritime situation assessment. This report is mainly dedicated to the mathematical formalisation of the risk game and the underlying maritime situation assessment problem. We propose an overarching framework for maritime situation assessment which clearly distinguishes between the elements of (1) context, (2) source quality and (3) situation, and considers their influence links. The model has three layers: variable layer, valuation layer and information quality layer. We adopt the algebraic framework of Valuation Algebras allowing a great flexibility in uncertainty representation and reasoning. In order to cover a wide range of uncertainty representations, and further study the impact of modelisation choices, we frame the problem into the belief function theory as it naturally extends both classical sets (hence classical logic) and probability theory. Furthermore, we use a graphical model which, besides efficient computation, allows a clear exposition of the problem and solution for a hopefully better understanding for the user. The analysis performed illustrates comparative reasoning schemes between players and automated reasoners. By testing a few different schemes, we have been able to identify players whose reasoning was consistent with evidential reasoning, or who answered to a threat assessment problem rather than an identification problem. We have also been able to highlight the impact of context and source quality. Rather than suggesting a normative way of reasoning, this study aims at characterising personal reasoning attitudes of experts. Knowing in advance the consequences of a particular reasoning scheme could help prevent some reasoning biases.

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