References of "Warnant, René"
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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 ▲]

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See detailOn the impact of ionospheric variability and disturbances on GNSS-based positioning applications
Stankov, Stanimir; Wautelet, Gilles ULg; Lejeune, Sandrine et al

in Geophysical Research Abstracts (2011, April), 13(ABS. No EGU2011-12067),

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See detailLocal ionospheric electron density profile reconstruction in real time from simultaneous ground-based GNSS and ionosonde measurements
Stankov, Stanimir; Stegen, Koen; Muhtarov, Plamen et al

in Advances in Space Research (2011), 47(7), 1172-1180

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See detailRMI-Dourbes ionosonde database - Status 2010
Stankov, Stanimir; Stegen, Koen; Jodogne, Jean-Claude et al

Report (2011)

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See detailLocal Operational Geomagnetic Index K Calculation (K-LOGIC) from digital ground-based magnetic measurements
Stankov, Stanimir; Stegen, Koen; Warnant, René ULg

Report (2011)

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See detailIonosphere modelling for Galileo single frequency users: illustration of the combination of the NeQuick model and GNSS data ingestion
Bidaine, Benoît ULg; Warnant, René ULg

in Advances in Space Research (2011), 47(2), 312-322

The ionospheric effect remains one of the main factors limiting the accuracy of Global Navigation Satellite Systems (GNSS) including Galileo. For single frequency users, this contribution to the error ... [more ▼]

The ionospheric effect remains one of the main factors limiting the accuracy of Global Navigation Satellite Systems (GNSS) including Galileo. For single frequency users, this contribution to the error budget will be mitigated by an algorithm based on the NeQuick global ionospheric model. This quick-run empirical model provides flexible solutions for combining ionospheric information obtained from various sources, from GNSS to ionosondes and topside sounders. Hence it constitutes an interesting simulation tool not only serving Galileo needs for mitigation of the ionospheric effect but also widening the use of new data. In this study, we perform slant TEC data ingestion - the optimisation procedure underlying the Galileo single frequency ionospheric correction algorithm - into NeQuick for a dozen locations around the world where both an ionosonde and a GPS receiver are installed. These co-located instruments allow us to compare measured and modelled vertical TEC showing for example global statistics or dependence towards latitude. We analyse measurements for the year 2002 (high solar activity level) giving an insight into the situation we could observe when Galileo reaches its Full Operation Capability, during the next solar maximum. At last we compare Galileo and GPS ionospheric corrections. For Galileo, we end up with an underestimation of 11% and 4% depending on the version of NeQuick embedded in the algorithm, as well as a 22% standard deviation. This means respectively twice, five and 1.5 times better than GPS. [less ▲]

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See detailK-type geomagnetic index nowcast with data quality control
Stankov, Stanimir; Stegen, Koen; Warnant, René ULg

in Annals of Geophysics = Annali di Geofisica (2011), 54(3), 285-295

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See detailTotal Electron Content Monitoring using triple frequency GNSS: results with Giove-A/-B data
Spits, Justine; Warnant, René ULg

in Advances in Space Research (2011), 47

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See detailSystèmes de positionnement par satellites
Warnant, René ULg

Learning material (2011)

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See detailThéorie des erreurs
Warnant, René ULg

Learning material (2011)

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See detailA GPS/GNSS dense network used to monitor ionospheric positioning error
Wautelet, Gilles ULg; Lejeune, Sandrine; Warnant, René ULg

Poster (2010, December)

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See detailThe RMI Space Weather and Navigation Systems (SWANS) project
Warnant, René ULg; Lejeune, Sandrine; Wautelet, Gilles ULg et al

Conference (2010, July)

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See detailUnderstanding the occurrence of mid-latitude ionospheric irregularities by using GPS, ionosonde and geomagnetic measurements
Wautelet, Gilles ULg; Lejeune, Sandrine; Stankov, Stan et al

Conference (2010, June 11)

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See detailA statistical study of the TEC storm-time response at European middle latitudes for use in ionospheric nowcast and forecast
Stankov, Stanimir; Stegen, Koen; Warnant, René ULg

in Doherty, P.; Hernandez-Pajares, M.; Juan, J.-M. (Eds.) et al The International Beacon Satellite Symposium 2010 (2010, June)

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See detailM-Ingestion: Simultaneous Ingestion of Ionosonde and GNSS Data into the NeQuick Model
Bidaine, Benoît ULg; Nava, Bruno; Stankov, Stanimir et al

in Doherty, P.; Hernández-Pajares, M.; Juan, J.-M. (Eds.) et al The International Beacon Satellite Symposium BSS2010 (2010, June)

The steady increase in volume and quality of ionospheric measurements allows for potential improvements in the existing ionospheric models. In particular ionosonde and Global Navigation Satellite Systems ... [more ▼]

The steady increase in volume and quality of ionospheric measurements allows for potential improvements in the existing ionospheric models. In particular ionosonde and Global Navigation Satellite Systems (GNSS) data provide complementary information for original developments regarding the NeQuick model, a quick-run empirical model of the electron density supplying flexible solutions for various applications. Indeed NeQuick is often used to investigate radiowave propagation issues: among others it has been implemented within the Galileo Single Frequency Ionospheric Correction Algorithm. The model is particularly suited to be used within an optimization procedure called ingestion. In this framework, an "effective ionization level" Az plays the role of solar activity input in order to fit a specific dataset eg of slant Total Electron Content (TEC). However larger discrepancies can then obviously be observed towards other parameters eg the F2-layer critical frequency foF2. This draws the interest for a multiple ingestion - or m-ingestion - scheme implying an adaptation towards several datasets by defining several effective parameters. In our study, we perform m-ingestion of ionosonde and GNSS data providing us with slant TEC. In fact it allows us to constrain the electron density profile slab thickness. For the purpose, a high solar activity period (year 2002) was analysed based on collocated digisonde and EUREF GNSS observations at a mid-latitude site, Dourbes (50.1◦N, 4.6◦E). In this way, we can gather some clues on expected ionospheric effects on Galileo applications during the next solar activity maximum. [less ▲]

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See detailOn the local operational geomagnetic index K calculation
Stankov, Stan; Stegen, Koen; Wautelet, Gilles ULg et al

Poster (2010, May 06)

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See detailMonitoring the ionospheric positioning error with a GNSS dense network
Wautelet, Gilles ULg; Lejeune, Sandrine; Warnant, René ULg

Conference (2010, May 06)

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See detailReconstruction de paramètres environnementaux à l'aide des GNSS: une opportunité pour les entreprises
Warnant, René ULg

Conference given outside the academic context (2010)

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