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See detailGalileo : une boussole spatiale européenne réglée par des ingénieurs belges
Bidaine, Benoît ULg

in Journal des Ingénieurs (Le) (2009), (121), 9-11

Detailed reference viewed: 133 (28 ULg)
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See detailGalileo ? Bien plus qu’un système de positionnement !
Warnant, René ULg

Conference given outside the academic context (2010)

Detailed reference viewed: 29 (5 ULg)
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See detailGalileo Local Component for the detection of atmospheric threats
Warnant, René ULg; Bavier, Michaël; Brenot, Hugues et al

in Goodman, John (Ed.) Proceedings of the 12th International Ionospheric Effects Symposium (IES2008) (2008, May)

Detailed reference viewed: 34 (2 ULg)
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See detailGalileo Local Component for the detection of atmospheric threats
Warnant, René ULg; Wautelet, Gilles ULg; Lejeune, Sandrine et al

Conference (2008, November)

Detailed reference viewed: 26 (7 ULg)
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See detailGalileo Single Frequency Ionospheric Correction: Performances in Terms of Position
Bidaine, Benoît ULg; Lonchay, Matthieu ULg; Warnant, René ULg

in GPS Solutions (2013), 17(1), 63-73

For GPS single frequency users, the ionospheric contribution to the error budget is estimated by the well-known Klobuchar algorithm. For Galileo, it will be mitigated by a global algorithm based on the ... [more ▼]

For GPS single frequency users, the ionospheric contribution to the error budget is estimated by the well-known Klobuchar algorithm. For Galileo, it will be mitigated by a global algorithm based on the NeQuick model. This algorithm relies on the adaptation of the model to slant Total Electron Content (sTEC) measurements. Although the performance specifications of these algorithms are expressed in terms of delay and TEC, the users might be more interested in their impact on positioning. Therefore, we assessed the ability of the algorithms to improve the positioning accuracy using globally distributed permanent stations for the year 2002 marked by a high level of solar activity. We present uncorrected and corrected performances, interpret these and identify potential causes for Galileo correction discrepancies. We show vertical errors dropping by 56–64 % due to the analyzed ionospheric corrections, but horizontal errors decreasing by 27 % at most. By means of a fictitious symmetric satellite distribution, we highlight the role of TEC gradients in residual errors. We describe mechanisms permitted by the Galileo correction, which combine sTEC adaptation and topside mismodeling, and limit the horizontal accuracy. Hence, we support further investigation of potential alternative ionospheric corrections. We also provide an interesting insight into the ionospheric effects possibly experienced during the next solar maximum coinciding with Galileo Initial Operation Capability. [less ▲]

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See detailGalileo Single Frequency Ionospheric Correction: Performances in Terms of Position
Bidaine, Benoît ULg; Warnant, René ULg

in Goodman, John M. (Ed.) 2011 Ionospheric Effects Symposium Proceedings (2011, May)

The ionospheric effect remains one of the main factors limiting GNSS accuracy. For GPS single frequency users, this contribution to the error budget is estimated thanks to the well-known Klobuchar ... [more ▼]

The ionospheric effect remains one of the main factors limiting GNSS accuracy. For GPS single frequency users, this contribution to the error budget is estimated thanks to the well-known Klobuchar algorithm. For Galileo, it will be mitigated by a global algorithm based on the NeQuick model. This algorithm relies on an optimisation procedure called ingestion. In this framework, an "effective ionisation level" Az plays the role of the solar activity information provided to the model in order to fit a specific dataset. For Galileo single frequency operation, daily Az values will be computed from slant Total Electron Content (sTEC) measurements performed within the ground segment and three coefficients will be broadcast to the users within the navigation message allowing them to run the model. The performance specifications of these algorithms are respectively expressed in terms of delay and TEC but the users might find more interest in their impact on positioning. Hence we propose to investigate their performances in terms of positioning accuracy. To this extent we compare positions of permanent stations calculated with and without the ionospheric correction to the actual ones which are known at the sub-centimetre level. Our simulation uses sTEC generated from Global Ionospheric Maps to provide the effective ionization level coefficients and GPS single frequency code measurements to compute positions. We present results for Brussels station in Belgium (mid-latitudes) and for 2002 (high solar activity level). It gives an interesting insight in the situation we could observe when Galileo reaches its Initial Operation Capability, during the next solar maximum. This study constitutes a first step in the development of a real-time service in the framework of the SWANS project of the University of Liège and the Royal Meteorological Institute of Belgium. As two Galileo receivers have been bought in this context, this service will be available for the In-Orbit Validation phase of Galileo. [less ▲]

Detailed reference viewed: 193 (19 ULg)
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See detailGalileo-based Collision Avoidance System
Wimmershoff, M.; Christen, Fréderic ULg

in FISITA World Automotive Congress 2010 (2010, June 01)

Nowadays, collision avoidance (CA) systems are an intensive research topic since the majority of all traffic accidents are collisions that are caused due to inattention or unadjusted driving behaviour of ... [more ▼]

Nowadays, collision avoidance (CA) systems are an intensive research topic since the majority of all traffic accidents are collisions that are caused due to inattention or unadjusted driving behaviour of the driver. In order to scan the vehicle's surrounding for potential crashes, up to date prototypic CA systems are based on on-board environmental sensors, such as camera or radar systems. The limited sensor covering area and the functionality of the used sensors under varying environmental conditions require an enormous effort to ensure a reliable detection of obstacles, and thus limit the application of the systems. In order to expand the operating field of such systems, a Galileo-based CA system will be developed within the project "GALILEO above". This advanced driver assistance system detects surrounding vehicles that are on collision course, and react autonomous, if the driver does not intervene to avoid the crash. For this purpose the system initiates an emergency stop or an emergency steering. For the development process of the CA system the Galileo test centre "automotiveGATE" in Aldenhoven, Germany will be used. Pseudolites will be installed at the automotiveGATE which provide Galileo-like navigation signals and enable the development and tuning of Galileo based vehicle systems. Thus, these systems are available on the market when the Galileo satellite system becomes operative. At the end of the project GALILEO above, first prototypes should demonstrate the potential of Galileo-based collision avoidance systems. In this paper the GALILEO above project will be introduced followed by a detailed description of the development process of the CA system. Furthermore, first results will be presented. [less ▲]

Detailed reference viewed: 23 (1 ULg)
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See detailGalileo-based Collision Avoidance System
Wimmershoff, M.; Christen, Fréderic ULg

in TRA Transport Research Arena Europe 2010 (2010, June 07)

Nowadays, collision avoidance (CA) systems are an intensive research topic since the majority of all traffic accidents are collisions that are caused due to inattention or unadjusted driving behaviour of ... [more ▼]

Nowadays, collision avoidance (CA) systems are an intensive research topic since the majority of all traffic accidents are collisions that are caused due to inattention or unadjusted driving behaviour of the driver. Up to date prototypic CA systems are based on on-board environmental sensors, such as camera or radar systems, in order to scan the vehicle’s surrounding for potential crashes. The functionality of the used sensors under varying environmental conditions and the limited sensor covering area require an enormous effort to ensure a reliable detection of obstacles, and thus limit the application of the systems. In order to expand the operating field of such systems, a GALILEO-based CA system will be developed within the project GALILEO-above. This advanced driver assistance system detects surrounding vehicles that are on collision course, and react autonomous, if the driver does not intervene to avoid the crash. For this purpose the system initiates an emergency stop or an emergency steering. For the development of the CA system the GALILEO test centre “Automotive Gate” in Aldenhoven, Germany will be used. On this test area pseudolites will be installed which provide GALILEO-like navigation signals. Thus, the development respectively tuning of GALILEO based vehicle systems will be enabled, so that they are available on the market when the GALILEO satellite system becomes operative. At the end of the project GALILEO-above, first prototypes should demonstrate the potential of GALILEO-based collision avoidance systems. In this paper the GALILEO-above project will be introduced followed by a detailed description of the development process of the CA system. Furthermore, first results will be presented. [less ▲]

Detailed reference viewed: 9 (0 ULg)
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See detailGallaicolichen, a new genus of foliicolous lichen with unique diaspores
Sérusiaux, Emmanuël ULg; Lücking, Robert

in Bibliotheca Lichenologica (2007), 95

Detailed reference viewed: 27 (0 ULg)
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See detailGallbladder mucocele: diagnosis, treatment and outcome in 4 dogs
Carofiglio, Francesca; Bongartz, Alexandre; Busoni, Valeria ULg et al

Poster (2004, July)

Detailed reference viewed: 10 (0 ULg)
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See detailGallo-romance I: Historical and etymological lexicography
Buchi, Eva; Renders, Pascale ULg

in Gouws, Rufus H.; Heid, Ulrich; Schweickard, Wolfgang (Eds.) et al Dictionaries: An International Encyclopedia of Lexicography. Supplementary Volume: Recent Developments with Focus on Electronic and Computational Lexicography (2013)

Detailed reference viewed: 84 (5 ULg)
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See detailGalloping and compact line
Lilien, Jean-Louis ULg

in Proceedings of the CIGRE Symposium on compacting overhead transmission lines (1991, May)

Galloping may alos be a problem for compact line. The paper is analysing that particular problem.

Detailed reference viewed: 10 (0 ULg)
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See detailGalloping Conductors
Lilien, Jean-Louis ULg; Havard, Dave; Van Dyke, Pierre

in Chan, John (Ed.) EPRI Transmission Line Reference Book : Wind-Induced Conductor Motion (2009)

The chapter describes galloping of overhead conductors. It includes an overview on the phenomenon, with information on its characteristics, types of galloping, damage resulting from it, and causes. The ... [more ▼]

The chapter describes galloping of overhead conductors. It includes an overview on the phenomenon, with information on its characteristics, types of galloping, damage resulting from it, and causes. The chapter also covers the mechanisms of galloping and reviews protection methods. [less ▲]

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See detailGalloping data base on single and bundle conductors prediction of maximum amplitudes
Lilien, Jean-Louis ULg; Havard, Dave

in IEEE Transactions on Power Delivery (2000), 15(N°2), 670-674

A data base of 166 cases has been analysed to produced formula to predict galloping amplitudes on power lines either for single conductor of bundle conductor lines.Calculation enhanced the prediction for ... [more ▼]

A data base of 166 cases has been analysed to produced formula to predict galloping amplitudes on power lines either for single conductor of bundle conductor lines.Calculation enhanced the prediction for single conductors but predict larger amplitudes for bundle. [less ▲]

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See detailGalloping of electrical lines in wind tunnel facilities
Chabart, Olivier; Lilien, Jean-Louis ULg

in Journal of Wind Engineering & Industrial Aerodynamics (1998), 74-76

Galloping on power lines is a difficult matter. In this paper a galloping has been reproduced in a wind tunnel on a section of an actual conductor with actual ice shape. Aerodynamics is first detailed ... [more ▼]

Galloping on power lines is a difficult matter. In this paper a galloping has been reproduced in a wind tunnel on a section of an actual conductor with actual ice shape. Aerodynamics is first detailed. Then flutter type and Den Hartod type galloping has been obtained in the wind tunnel depending on changeable ratio vertical to torsional frequencies. [less ▲]

Detailed reference viewed: 29 (0 ULg)
See detailGALOCAD : GALileo LOcal Component for nowcasting and forecasting Atmospheric Disturbances
Warnant, René ULg; Kutiev, Ivan; Jodogne, Jean-Claude et al

Conference (2006)

Detailed reference viewed: 16 (0 ULg)
See detailGALOCAD User interface
Warnant, René ULg; Wautelet, Gilles ULg

Report (2008)

Detailed reference viewed: 25 (4 ULg)
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See detailLe galop des conducteurs. Etat de l'art.
Lilien, Jean-Louis ULg

in Electra (2007), 232

Power line galloping is a large vibration (up to the sag) at very low frequency (fraction of Hz) occuring on power line spans under heavy wind and cold temperature, with ice/snow deposit. Galloping is due ... [more ▼]

Power line galloping is a large vibration (up to the sag) at very low frequency (fraction of Hz) occuring on power line spans under heavy wind and cold temperature, with ice/snow deposit. Galloping is due to aerodynamic or aeroelastic instability. It may cause dramatic damages on conductor, hardware and towers. [less ▲]

Detailed reference viewed: 33 (2 ULg)
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See detailGame over : mathématiques et jeux vidéos
Rigo, Michel ULg

Learning material (2011)

Le but de cet exposé est de présenter, à travers plusieurs exemples simples, des outils mathématiques utilisés dans la conception de jeux vidéos (par exemple : projections, produits scalaire et vectoriel ... [more ▼]

Le but de cet exposé est de présenter, à travers plusieurs exemples simples, des outils mathématiques utilisés dans la conception de jeux vidéos (par exemple : projections, produits scalaire et vectoriel, calcul matriciel pour l'animation en 3D, fonctions et fractales pour la création de textures procédurales et de matériaux, etc.). Les exemples seront choisis en fonction des connaissances préalables du public (analyse, algèbre, géométrie) et permettront de mettre en évidence l'utilité en infographie des concepts vus au cours de mathématiques. [less ▲]

Detailed reference viewed: 322 (38 ULg)