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Precise position determination using a Galileo E5 single-frequency receiver / H. Toho Diessongo in GPS solutions, vol 18 n° 1 (january 2014)  

Public [article]  inGPS solutions > vol 18 n° 1 (january 2014) . - pp 73 - 83 Titre : Precise position determination using a Galileo E5 single-frequency receiver Type de document : Article/Communication Auteurs : H. Toho Diessongo, Auteur ; Torben Schüler, Auteur ; Stefan Junker, Auteur Année de publication : 2014 Article en page(s) : pp 73 - 83 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes IGN] code GNSS [Termes IGN] positionnement par Galileo [Termes IGN] positionnement ponctuel précis [Termes IGN] résolution d'ambiguïté [Termes IGN] retard ionosphèrique [Termes IGN] signal Galileo Résumé : (auteur) The European Galileo system offers one dedicated signal that is superior to all other signals currently available in space, namely the broadband signal E5. This signal has a bandwidth of at least 51 MHz using an AltBOC modulation. It features a code range noise at centimeter level. Additionally, the impact of multipath effects on this signal is significantly lower compared to all other available GNSS signals. These unique features of Galileo E5 drastically improve the precision of code range measurements and hence enable precise single-frequency positioning. Certain scientific and non-scientific applications in the positioning domain could likely benefit from the exploitation of E5 measurements. A positioning approach based on an additive combination of code range and carrier phase measurements (CPC—“code-plus-carrier”) to eliminate the ionospheric delay could be used to perform precise positioning over long distances. Unfortunately, this derived observable contains the ambiguity term as an additional unknown what normally requires longer observation windows in order to allow sufficient convergence of the ambiguity parameters. For this reason, a rapid convergence algorithm based on Kalman filtering was implemented in addition to the conventional CPC approach that is also discussed. The CPC-based results yield a positioning precision of 2–5 cm after a convergence time of about 3 h. The rapid convergence filter allows fixing the ambiguity terms within a few minutes, and the obtained position results are at the sub-decimeter level. Regarding one selected test, real data from Galileo experimental satellite GIOVE A were used in order to confirm our assumptions. However, since the current Galileo constellation is not sufficient for real-world positioning trials yet, all major results are based on simulated data. Numéro de notice : A2014-655 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-013-0311-2 En ligne : https://doi.org/10.1007/s10291-013-0311-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77826 [article]

Exploiting the Galileo E5 wideband signal for improved single-frequency precise positioning / H. Toho Diessongo in Inside GNSS, vol 7 n° 5 (September - October 2012) 

Public [article]  inInside GNSS > vol 7 n° 5 (September - October 2012) . - pp 64 - 73 Titre : Exploiting the Galileo E5 wideband signal for improved single-frequency precise positioning Type de document : Article/Communication Auteurs : H. Toho Diessongo, Auteur ; Heike Bock, Auteur ; Torben Schüler, Auteur ; et al., Auteur Année de publication : 2012 Article en page(s) : pp 64 - 73 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] géopositionnement [Termes IGN] positionnement ponctuel précis [Termes IGN] précision centimétrique [Termes IGN] récepteur monofréquence [Termes IGN] signal Galileo Résumé : (Auteur) Single-frequency positioning can undoubtedly be improved with the deployment of new GNSS systems and the accompanying availability of new signals. Among various innovations, the Galileo E5 broadband signal deserves special attention. Its unique features, including the AltBOC modulation scheme, will drastically boost code range precision, both in terms of reduced code noise as well as with respect to multipath. Precise single-frequency positioning will be feasible at centimeter level, benefiting both scientific and non-scientific applications. This article demonstrates the expected performance of E5 for selected land applications and precise orbit determination of low Earth orbiting satellites. Numéro de notice : A2012-508 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31954 [article]

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On ground-based GPS tropospheric delay estimation / Torben Schüler (2001)  

Public Titre : On ground-based GPS tropospheric delay estimation : Vollständiger Abdruck der an der Fakultät für Bauingenieur- und Vermessungswesen der Universität der Bundeswehr München zur Erlangung des akademischen Grades eines Doktors der Ingenieurwissenschaften (Dr.-Ing.) eingereichten Dissertation Type de document : Thèse/HDR Auteurs : Torben Schüler, Auteur Editeur : Munich : Universität der Bundeswehr Année de publication : 2001 Importance : 364 p. Format : 21 x 30 cm Note générale : bibliographie mémoire de docteur ingénieur de l'université de Munich Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] retard troposphérique Résumé : (auteur) NAVSTAR GPS has become an important aid in navigation and precise space geodesy. Permanent tracking networks like the global IGS net of the International GPS Service for Geodynamics and regional densifications like the German Reference Frame GREF have become very valuable for many scientific applications. For parameter estimation in largescale networks, two major error sources have to be reduced, namely the orbit error of the GPS space vehicles and the propagation delay in the troposphere. In 1992, the IGS started to produce precise GPS orbits which became a standard product of high precision that virtually eliminated orbit uncertainties from the list of significant contributors to the overall error budget. The remaining problem is that of modeling wet delays with high precision. All conventional models have to fail in this task due to the impossibility of modeling wet delays solely from surface measurements like temperature and relative humidity. Actually, the non-hydrostatic component of the tropospheric propagation delay is highly influenced by the distribution of water vapor in the lower troposphere which cannot be sufficiently predicted with sole help of surface measurements. A work-around is to include atmospheric parameters as additional unknowns in the analysis of GPS data from permanent monitor stations that turns out to improve the quality of position estimates. Moreover, knowledge of zenith wet delays allows to obtain a highly interesting value for climatology and meteorology: integrated or precipitable water vapor being important for the energy balance of the atmosphere and holds share of more than 60% of the natural greenhouse effect. GPS can thereby contribute to the improvement of climate models and weather forecasting. This work outlines the application of ground-based GPS to climate research and meteorology without omitting the fact that precise GPS positioning can also highly benefit from using numerical weather models for tropospheric delay determination for applications where GPS troposphere estimation is not possible, for example kinematic and rapid static surveys. In this sense, the technique of GPS-derived tropospheric delays is seen as mutually improving both disciplines, precise positioning as well as meteorology and climatology. Chapters 1 to 4 constitute the theoretical part of this study with first introducing the reader to the importance of water vapor and tropospheric delays (Chapter 1) and outlining the principles of GPS data processing (Chapter 2) with special emphasis on tropospheric delay modeling (Chapter 3). Furthermore, a brief introduction to numerical weather models and extraction methods for needed data is given (Chapter 4) and approaches to combine both data sets - tropospheric delays from numerical weather fields and GPS delays - are described. Chapters 5 to 7 describe several experiments to validate and assess the quality of numerical weather model data (Chapter 5), GPS-derived troposphere propagation delays (Chapter 6) and combined solutions (Chapter 7). Finally, a summary of the application of ground-based GNSS for tropospheric delay estimation is given (Chapter 8). Note de contenu : 1- Introduction 2- Principles of GPS data processing 3- Modeling and estimating tropospheric propagation delays 4- Application of numerical weather models 5- Validation of numerical weather model data 6- GPS validation experiments 7- Quality assessment of TROPEX data Numéro de notice : 14864 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Note de thèse : mémoire de docteur ingénieur : : Université de Munich : 2001 DOI : sans En ligne : https://athene-forschung.unibw.de/85240?id=85240 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=75853