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Auteur Sylvain Loyer |
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Affiner la recherche Interroger des sources externesGRGS numerical simulations for a GRASP-like mission: A way to reach the GGOS goal for terrestrial reference frame / Arnaud Pollet in Journal of geodesy, vol 97 n° 5 (May 2023)
Titre : GRGS numerical simulations for a GRASP-like mission: A way to reach the GGOS goal for terrestrial reference frame Type de document : Article/Communication Auteurs : Arnaud Pollet Année de publication : 2023 Article en page(s) : n° 45 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] International DORIS Service
[Termes IGN] mission spatiale
[Termes IGN] orbitographie
[Termes IGN] positionnement par ITGB
[Termes IGN] positionnement par télémétrie laser sur satellite
[Termes IGN] repère de référenceRésumé : (auteur) In 2009, the geoscience community has fixed an objective of 1 mm accuracy and 0.1 mm/yr stability for the terrestrial reference frame (TRF) realization (Global Geodetic Observing System, GGOS, Meeting the Requirements of a Global Society on a Changing Planet in 2020, Plag and Pearlman in Global geodetic observing system: meeting the requirements of a global society on a changing planet in 2020. Springer, Berlin, 2009. https://doi.org/10.1007/978-3-642-02687-4). This accuracy and stability are needed for diversified studies like climate change, tectonic sciences and more generally any geoscience requiring the use of an accurate and precise TRF. Unfortunately, they are still not reached by the last International Terrestrial Reference Frame. To reach this goal, the use of “multi-technique” satellites as “space-ties” has been studied since 2011 and a few proposals have been made in response to different space agency calls: the Geodetic Reference Antenna in Space (GRASP) mission—NASA Earth Venture 2 call, Eratosthenes-GRASP (E-GRASP)—ESA Earth Explorer 9 (EE9) call, MOBILE—ESA EE10 call, MARVEL—CNES Séminaire de Prospective Scientifique 2019). In this article, we present the numerical simulations carried out by the French Groupe de Recherche de Géodésie Spatiale (GRGS) for the E-GRASP proposal in response to the ESA EE-9 call and their improvements carried out afterwards. These simulations aim to answer three different questions:
Is it possible to reach the GGOS requirements for the TRF with the measurements of a GRASP-like satellite like E-GRASP alone?
If it is possible, which level of accuracy for the positioning of the on-board antennas is needed?
What is the minimal lifetime of a E-GRASP mission to reach the GGOS requirements?
The results of these simulations show that a E-GRASP satellite can allow us to reach, after five years, an accuracy close to 1 mm and a stability better than 0.1 mm/yr for the TRF. However, it is necessary to ensure a positioning better than 1 mm for the on-board antennas. We therefore encourage the new ESA GENESIS mission proposal, accepted during the ESA last Ministerial meeting on 23rd November 2022, which takes up the concept of a GRASP-type satellite.Numéro de notice : A2023-227 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-023-01730-4 Date de publication en ligne : 15/05/2023 En ligne : https://doi.org/10.1007/s00190-023-01730-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=103247
in Journal of geodesy > vol 97 n° 5 (May 2023) . - n° 45[article]
Titre : On the interoperability of IGS products for precise point positioning with ambiguity resolution Type de document : Article/Communication Auteurs : Simon Banville, Auteur ; Jianghui Geng, Auteur ; Sylvain Loyer, Auteur ; et al., Auteur Année de publication : 2020 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] horloge du satellite
[Termes IGN] international GPS service for geodynamics
[Termes IGN] interopérabilité
[Termes IGN] longitude
[Termes IGN] positionnement cinématique
[Termes IGN] positionnement par GNSS
[Termes IGN] positionnement ponctuel précis
[Termes IGN] positionnement statique
[Termes IGN] précision millimétrique
[Termes IGN] résolution d'ambiguïtéRésumé : (auteur) Techniques enabling precise point positioning with ambiguity resolution (PPP-AR) were developed over a decade ago. Several analysis centers of the International GNSS Service (IGS) have implemented such strategies into their software packages and are generating (experimental) PPP-AR products including satellite clock and bias corrections. While the IGS combines individual orbit and clock products as standard to provide a more reliable solution, interoperability of these new PPP-AR products must be confirmed before they can be combined. As a first step, all products are transformed into a common observable-specific representation of biases. It is then confirmed that consistency is only ensured by considering both clock and bias products simultaneously. As a consequence, the satellite clock combination process currently used by the IGS must be revisited to consider not only clocks but also biases. A combination of PPP-AR products from six analysis centers over a one-week period is successfully achieved, showing that alignment of phase clocks can be achieved with millimeter precision thanks to the integer properties of the clocks. In the positioning domain, PPP-AR solutions for all products show improved longitude estimates of daily static positions by nearly 60% over float solutions. The combined products generally provide equivalent or better results than individual analysis center contributions, for both static and kinematic solutions. Numéro de notice : A2020-150 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-019-01335-w Date de publication en ligne : 03/01/2020 En ligne : https://doi.org/10.1007/s00190-019-01335-w Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94782
in Journal of geodesy > vol 94 n°1 (January 2020)[article]
Titre : Multi-GNSS Hybridization for Precise Positioning Type de document : Thèse/HDR Auteurs : Georgia Katsigianni, Auteur ; Félix Perosanz, Directeur de thèse ; Sylvain Loyer, Directeur de thèse Editeur : Toulouse : Université de Toulouse 3 Paul Sabatier Année de publication : 2019 Importance : 143 p. Format : 21 x 30 cm Note générale : Thèse en vue de l'obtention du Doctorat de l'Université de Toulouse 3 Paul Sabatier, Spécialité Sciences de la Terre et des Planètes Solides Langues : Anglais (eng) Descripteur : [Termes IGN] données Galileo
[Termes IGN] données GPS
[Termes IGN] orbitographie
[Termes IGN] positionnement cinématique
[Termes IGN] positionnement par GNSS
[Termes IGN] positionnement ponctuel précis
[Termes IGN] résolution d'ambiguïté
[Vedettes matières IGN] Traitement de données GNSSIndex. décimale : THESE Thèses et HDR Résumé : (auteur) GNSS are widely used for precise positioning applications of geosciences and especially space geodesy. So far, mainly the existing GPS was extensively used for scientific applications. With the arrival of the new European Galileo system it became imperative to include the new system in the studies and check the new capabilities that it will bring as a system alone and as combined together with the others in a Multi-GNSS processing. The CNES/CLS analysis center of the IGS is weekly calculating GNSS (GPS, GLONASS and Galileo) products that can be taken from any kind of user to perform precise positioning. A way to achieve the best accuracy possible is to resolve the unknown integer ambiguities of the phase measurements. Up until now, the CNES/CLS was performing ambiguity resolution to the GPS system using the zero-difference method. In this way they are able to deliver precise satellite orbits and precise clock products with phase fixed ambiguities. The goal of this work was to implement and validate if the method can be also applied for the Galileo system. The method applied from the CNES/CLS is consisting of two further steps. The first one is the resolution of the Wide-Lane ambiguities. The Galileo Wide-Lane satellite biases have been proven to be stable over long periods of time. In addition, there is homogeneity in the way they are observed from different types of receivers. These findings were used and the Wide-Lane biases were successfully resolved with nearly 100% success rate percentage. The second step of zero-difference method is the Narrow-Lane ambiguity resolution. This step was executed for the Galileo system together with the GPS system in a Multi-GNSS Precise Orbit Determination processing. Galileo ambiguity fixing success percentage is around 93%, nearly similar to the one of the GPS system. The integer property of the Galileo phase clocks is demonstrated. Both orbit overlaps and orbit validation using SLR validation methods showed that ambiguity resolution improves mainly in the normal and the along track direction. Galileo orbit overlaps in 3D RMS showed an improvement of around 50%, from around 7 cm to 3.5 cm. The results of this work were used by the CNES/CLS IGS AC that has announced the delivery of weekly Galileo precise orbits, clocks and Wide-Lane satellite biases. A new method is also introduced on how to compare ambiguity resolution results for a common overlapping period. This method is also used to speculate the agreement and the disagreement between two different daily solutions. Finally, it was examined the post-processed kinematic PPP and PPP-AR using Galileo-only, GPSonly and Multi-GNSS (GPS + Galileo) constellations. The interest was to validate the accuracy for each GNSS system individually but also of their combination. Results showed that Galileoonly positioning accuracy is nearly at the same level of accuracy as GPS-only. The use of Galileo system improves the performance of the GPS positioning giving mm level repeatability. The contribution of Galileo ameliorates the positioning accuracy around 30% in all directions(comparison GPS PPP-AR and Multi-GNSS PPP-AR). This proved that the Galileo constellation together with GPS will give improved precise positioning with respect to the current GPS-only.
All these are indications that the Galileo system will contribute to precise positioning required by geoscience applications through a Multi-GNSS (GPS + Galileo) solution.Note de contenu : 1- Introduction
2- GNSS in science
3- GNSS measurements
4- Galileo Wide-Lane AR
5- Galileo Narrow-Lane AR
6- Precise Point Positioning
7- Conclusions and SuggestionsNuméro de notice : 28511 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse française Note de thèse : Thèse de Doctorat : Sciences de la Terre et des Planètes Solides : Toulouse 3 : 2019 Organisme de stage : Geosciences Environnement Toulouse nature-HAL : Thèse DOI : sans En ligne : http://www.theses.fr/2019TOU30209 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97142
Titre : Computation of GPS P1–P2 differential code biases with JASON-2 Type de document : Article/Communication Auteurs : Gilles Wautelet, Auteur ; Sylvain Loyer, Auteur ; Flavien Mercier, Auteur ; Félix Perosanz, Auteur Année de publication : 2017 Article en page(s) : pp 1619 - 1631 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] code GPS
[Termes IGN] corrélation
[Termes IGN] données Jason
[Termes IGN] erreur systématique
[Termes IGN] GPS en mode différentiel
[Termes IGN] orbitographie
[Termes IGN] plasmasphère
[Termes IGN] teneur verticale totale en électronsRésumé : (Auteur) GPS Differential Code Biases (DCBs) computation is usually based on ground networks of permanent stations. The drawback of the classical methods is the need for the ionospheric delay so that any error in this quantity will map into the solution. Nowadays, many low-orbiting satellites are equipped with GPS receivers which are initially used for precise orbitography. Considering spacecrafts at an altitude above the ionosphere, the ionized contribution comes from the plasmasphere, which is less variable in time and space. Based on GPS data collected onboard JASON-2 spacecraft, we present a methodology which computes in the same adjustment the satellite and receiver DCBs in addition to the plasmaspheric vertical total electron content (VTEC) above the satellite, the average satellite bias being set to zero. Results show that GPS satellite DCB solutions are very close to those of the IGS analysis centers using ground measurements. However, the receiver DCB and VTEC are closely correlated, and their value remains sensitive to the choice of the plasmaspheric parametrization. Numéro de notice : A2017-617 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-017-0638-1 Date de publication en ligne : 19/05/2017 En ligne : https://doi.org/10.1007/s10291-017-0638-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86927
in GPS solutions > vol 21 n° 4 (October 2017) . - pp 1619 - 1631[article]
Titre : Multi-technique combination of space geodesy observations: Impact of the Jason-2 satellite on the GPS satellite orbits estimation Type de document : Article/Communication Auteurs : Myriam Zoulida Année de publication : 2016 Article en page(s) : pp 1376 - 1389 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] données Jason
[Termes IGN] orbitographie
[Termes IGN] satellite GPS
[Vedettes matières IGN] Traitement de données GNSSRésumé : (auteur) In order to improve the Precise Orbit Determination (POD) of the GPS constellation and the Jason-2 Low Earth Orbiter (LEO), we carry out a simultaneous estimation of GPS satellite orbits along with Jason-2 orbits, using GINS software. Along with GPS station observations, we use Jason-2 GPS, SLR and DORIS observations, over a data span of 6 months (28/05/2011–03/12/2011). We use the Geophysical Data Records-D (GDR-D) orbit estimation standards for the Jason-2 satellite. A GPS-only solution is computed as well, where only the GPS station observations are used. It appears that adding the LEO GPS observations results in an increase of about 0.7% of ambiguities fixed, with respect to the GPS-only solution. The resulting GPS orbits from both solutions are of equivalent quality, agreeing with each other at about 7 mm on Root Mean Square (RMS). Comparisons of the resulting GPS orbits to the International GNSS Service (IGS) final orbits show the same level of agreement for both the GPS-only orbits, at 1.38 cm in RMS, and the GPS + Jason2 orbits at 1.33 cm in RMS. We also compare the resulting Jason-2 orbits with the 3-technique Segment Sol multi-missions d’ALTimétrie, d’orbitographie et de localisation précise (SSALTO) POD products. The orbits show good agreement, with 2.02 cm of orbit differences global RMS, and 0.98 cm of orbit differences RMS on the radial component. Numéro de notice : A2016-963 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2016.06.019 Date de publication en ligne : 22/06/2016 En ligne : http://dx.doi.org/10.1016/j.asr.2016.06.019 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83580
in Advances in space research > vol 58 n° 7 (October 2016) . - pp 1376 - 1389[article]
