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Analysis of GNSS raw observations in PPP solutions / Erik Schönemann (2014)    

Public Titre : Analysis of GNSS raw observations in PPP solutions Type de document : Thèse/HDR Auteurs : Erik Schönemann, Auteur Editeur : Darmstadt [Allemagne] : Technische Universität Darmstadt Année de publication : 2014 Collection : Schriftenreihe der Fachrichtung Geodäsie num. 42 Importance : 133 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-935631-31-0 Note générale : Vom Fachbereich Bau- und Umweltingenieurwissenschaften der Technischen Universität Darmstadt zur Erlangung des akademischen Grades eines Doktor-Ingenieurs (Dr.-Ing.) genehmigte Dissertation Langues : Anglais (eng) Descripteur : [Termes IGN] données GNSS [Termes IGN] positionnement ponctuel précis [Termes IGN] retard ionosphèrique [Termes IGN] retard troposphérique [Termes IGN] traitement de données GNSS [Termes IGN] traitement du signal [Vedettes matières IGN] Traitement de données GNSS Index. décimale : 30.61 Systèmes de Positionnement par Satellites du GNSS Résumé : (auteur) Global navigation satellite systems (GNSS) are an essential component in many areas of our daily life. They find application in diverse fields of private, commercial and scientific activities and are employed to meet the needs of police and military. Their fundamental importance for industrial countries is not the least the triggering point for the continuing modernisation of the existing and the development of new systems. The global satellite navigation systems are supplemented by regional satellite navigation systems (RNSS) and satellite based augmentation systems (SBAS). The diversity of systems, applied signal modulations and carrier frequencies, in particular in their combination, provide a broad range of opportunities along with new challenges. The work presented herein focuses on the use of satellite navigation systems for precise positioning and timing applications and scientific analysis. For best and comprehensive results, an equivalent combination of all available systems and signals is a fundamental requirement. For these reasons, relative approaches based on observation differences are rather inappropriate. Hence, this thesis focuses primarily on the method of precise point positioning (PPP) by waiving linear combinations. The objective is the development of a universal PPP analysis approach for standalone PPP and network solutions. Raw observations conserve the physical properties of original observation. This allows a detailed analysis of individual signal characteristics, but leads to the necessity of handling them. The utilisation of raw observations comes along with maximum flexibility. It allows for the application of physical error models as well as individual weighting and edition of all individual observation types. The possibility of a joint processing of all observations and the estimation of all parameters in a single run results in a significant simplification of the processing procedure. The first part of the thesis provides a general introduction to conventional GNSS analysis and highlights the limitations thereof. The second part introduces the technique of raw observations processing. It highlights the differences from the common ionosphere free processing approach and discusses the challenges. The concept presented for the analysis of GNSS raw observations is flexible and adjustable to any kind of GNSS application. This flexibility is attributed to a variety of different possible interpretations of the raw observation equation. In the frame of this thesis, a selection of different interpretations is introduced and demonstrated. One of the most important parameters for the analysis of raw observations is the so-called uncalibrated signal delays. The work presented exemplarily demonstrates their characteristics and discusses their implications for the analysis. For maximum stability of the results, it is common practice to resolve and apply integer carrier phase ambiguities. The presented work discusses and demonstrates the feasibility of this methodology for the implemented approach. It shows that the new approach simplifies the resolution of inter-GNSS carrier phase ambiguities and extends the spectrum of resolvable ambiguities. It is demonstrated that the proposed concept provides an “at least” equivalent alternative to the common processing strategies, applicable for highly precise standalone, as well as network PPP solutions, allowing for the simplified, consistent processing of different numbers of observation, suitable for an optimal, flexible, equivalent, joint processing of arbitrary GNSS observation types. It introduces a new dimension of analysis, with direct access to all individual observations and parameters. Note de contenu : 1 Introduction 1.1 Objectives of the research 1.2 External reference solutions 1.3 Outline of this thesis 2 Principles of Global Navigation Satellite Systems 2.1 General architecture 2.2 Geodetic reference systems and timescales 2.3 Navigation signals 3 Conventional GNSS analysis 3.1 Receiver system 3.2 GNSS observation modelling 3.3 Parameter estimation 3.4 Resolution of carrier phase ambiguities 4 Analysis of raw GNSS observations 4.1 Benefits of raw observation analyses 4.2 Challenges of raw observation analyses 4.3 Ambiguity resolution for raw observations 5 Implementation and general processing strategy 5.1 Software implementation 5.2 GNSS processing strategy applied 5.3 Parameter estimation setup 5.4 Observation weighting and screening criteria 6 Analysis of uncalibrated signal delays 6.1 Receiver-dependent signal delays 6.2 Satellite-related signal delays 6.3 Summary of analyses of uncalibrated signal delays 7 Applicability of raw observation processing 7.1 Applicability for global networks 7.2 Applicability for standalone PPP 7.3 Optimisation via bias calibration and ambiguity resolution 8 Conclusions 8.1 Challenges of raw observation analysis 8.2 Benefits and capabilities of raw observation analysis 8.3 Ambiguity fixing in the case of raw observations 8.4 Experiments and analyses 8.5 Future work Numéro de notice : 14900 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Note de thèse : PhD : Fachbereich Bau- und Umweltingenieurwissenschaften : Technische Universität Darmstadt : 2014 DOI : sans En ligne : http://tuprints.ulb.tu-darmstadt.de/3843/7/Schoenemann_Dissertation_TUD.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76785

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Where is GIOVE-A exactly? Using microwaves and laser ranging for precise orbit determination / Erik Schönemann in GPS world, vol 20 n° 7 (July 2009)

Public [article]  inGPS world > vol 20 n° 7 (July 2009) . - pp 42 - 50 Titre : Where is GIOVE-A exactly? Using microwaves and laser ranging for precise orbit determination Type de document : Article/Communication Auteurs : Erik Schönemann, Auteur ; Tim A. Springer, Auteur ; R. Langley, Auteur ; et al., Auteur Année de publication : 2009 Article en page(s) : pp 42 - 50 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] constellation Galileo [Termes IGN] GIOVE (satellite) [Termes IGN] orbitographie [Termes IGN] télémétrie laser sur satellite Résumé : (Auteur) We use them for listening to music, for routine surgeries, for making a point in a presentation, and even for hanging pictures straight. Of course, I'm talking about lasers. Invented in 1960, the laser (an acronym for light amplification by the stimulated emission of radiation) has become ubiquitous in modem society. Every CD and DVD player has one. Many printers use them. But lasers are also used in a wide range of industrial and scientific applications including determining the orbits of satellites through satellite laser ranging (SLR). In the SLR technique, pulses of laser light from a ground reference station are directed at satellites equipped with an array of coner-cube retroreflectors, which direct the pulses back towards a collocated receiving, telescope. By accurately measuring the two-way travel times of the pulses and knowing location of the station and other operating parameters, the positions of the satellites can be determined. A network of SLR reference stations around the globe is used to monitor the orbits of satellites over time and their variations have been used by scientists to improve our knowledge of the Earth's gravity field ; to study the long term dynamics of the solid Earth, oceans, and atmosphere; and even to verify predictions of the General Theory of Relativity. The first SLR measurements were obtained from the Beacon Explorer-B satellite which launched in october 1964. Since then, dozens of satellite equipped with corner-cube retroreflectors have been launched including a number of radio-navigation satellites. Every GLONASS satellite is equipped with retroreflectors and two GPS satellite have been equipped - SVN35/PRN05 and SVN36/PNR06. The COMPASS-M1 satellite in medium earth orbit carries retroreflectors, as do both GIOVE-A and -B, the Galileo test satellites. Precise orbit determination of radio-navigation satellites using SLR has the advantage of being unaffected by any onboard satellite electronics and associated signal biases. Radiometric observations of a satellite's microwave signals, on the other hand, are influenced by the satellite's clock, for example, and its effect must be estimated to obtain precise (and accurate) satellite orbits for navigation and positioning. Therefore, a comparison of SLR-and microwave derived orbits can be very useful for studying the performance of the data measurement and orbit-determination processes of both techniques. In this month's column, we take a look at some work being carried out to precisely determine the orbit of the GIOVE-A test satellite using SLR and microwave observations. This preliminary investigation will benefit the procedures to be implemented for the future Galileo constellation. Copyright Questex Media Group Numéro de notice : A2009-282 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29912 [article]

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