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GNSS antenna orientation based on modification of received signal strengths / David Eugen Grimm (2012)
Titre : GNSS antenna orientation based on modification of received signal strengths Type de document : Thèse/HDR Auteurs : David Eugen Grimm, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2012 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 88 Importance : 148 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-33-8 Note générale : Bibliographie
Doctoral thesisLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] antenne GNSS
[Termes IGN] détection du signal
[Termes IGN] orientation
[Termes IGN] signal GNSSIndex. décimale : 30.70 Navigation et positionnement Résumé : (Editeur) This work presents a concept to determine the orientation of a single GNSS antenna. When the orientation of the antenna is known, the presented approach can also be used for detection of multipath and reflected signals as well as spoofing signals. The orientation of the antenna is calculated using the direction of arrival (DOA) of the satellites' signals. Because the DOAs of the satellites' signals are not detectable with a standard GNSS antenna, the directional antenna pattern of the ntenna used is modified. The antenna pattern is modified by partially covering the antenna with a material that attenuates the signals in the band spectrum of GNSS. The attenuating material is rotated above the antenna, thereby influencing the received signal strength of the different satel lites. The signal strength is indicated by the carrier-to-noise density C/N0. Analysing the C/N0 of different satellites allows determining the DOA of each satellite's signal in relation to the antenna. Knowing the satellites' positions from the broadcast ephemerides and the antenna position allows calculation of the antenna orientation as well as the theoretically expected DOAs. Based on the instant approach, the real DOA of each satellite's signal is determined. By comparing the expected DOAs with the real DOAs, multipath and reflected signals as well as spoofing signals are determinable. Excluding these signals from the position and orientation calculation can remove systematic biases and, therefore, improve the accuracy.
Knowledge of the orientation completes the positioning information and is necessary for navigation applications. For precise GNSS measurements, the orientation of the antenna must be known to implement correction models for the antenna phase centre offset (PCO) and phase centre variation (PCV). Under optimal conditions, orientation information with an uncertainty of 5 degrees is achievable after a 2-minute measurement while an orientation with an uncertainty below 1 degree is achievable by measuring for several hours. Under poor condition s, an uncertainty of 5 degrees is achievable as well; however, because of systematic influences, the uncertainty will not improve significantly over a longer measuring time. A comparison of the obtained orientation value to a reference value verifies the correctness of the concept.Note de contenu : 1 Introduction
1.1 Global Navigation Satellite Systems (GNSS).
1.2 Why Orientation?
1.3 Determination of Orientation by GNSS
1.4 Introducing the Term Orientation
1.5 North Direction and Terrestrial Reference System.
1.6 Outline of this Thesis.
2 State of the Art in GNSS Orientation Determination.
2.1 System Types
2.2 Description of the Effects and Concepts Used
2.3 Overview of Existing Methods and Systems
2.4 Chapter Conclusion
3 GNSS Antennas and Signals
3.1 Antennas
3.2 Antenna Fields
3.3 Antenna Characteristics
3.4 GNSS Antenna Types
3.5 Geodetic GNSS Antennas
3.6 GNSS Signals
3.7 Chapter Conclusion
4 Mathematical Models for Satellite Orbits
4.1 Broadcast Ephemerides, Almanac, and GPS Time
4.2 Orbit Calculation
4.3 Satellite Motion
4.4 Chapter Conclusion
5 Orientation Finding with NORDIS
5.1 Required Accuracy
5.2 Measurement Concept of NORDIS
5.3 Measuring System
5.4 Experimental Setup
5.5 Chapter Conclusion
6 Orientation Calculation
6.1 Periodic Model
6.2 Correlation Approach
6.3 Chapter Conclusion
7 Verification of the Results
7.1 Dependency of the Measuring Duration on the Orientation Uncertainty.
7.2 Verification of the Components
7.3 Chapter Conclusion
8 Conclusion and Outlook
8.1 Conclusion
8.2 Possible Use Cases
8.3 Possible Improvements of NORDIS
8.4 Limitations of NORDISNuméro de notice : 15702 Affiliation des auteurs : non IGN Autre URL associée : URL ETH Zurich Thématique : POSITIONNEMENT Nature : Thèse étrangère DOI : 10.3929/ethz-a-007597299 En ligne : https://www.sgc.ethz.ch/sgc-volumes/sgk-88.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62765 Réservation
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Titre : GPS meteorology : with focus on climate applications Type de document : Thèse/HDR Auteurs : Tong Ning, Auteur Editeur : Göteborg [Suède] : Chalmers University of Technology Année de publication : 2012 Importance : 82 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-91-7385-675-1 Note générale : Thesis for the degree of doctor of philosophy, Department of Earth and Space Sciences, Chalmers University of Technology, Gothenburg, Sweden Langues : Anglais (eng) Descripteur : [Termes IGN] données GPS
[Termes IGN] modèle atmosphérique
[Termes IGN] retard troposphérique zénithal
[Termes IGN] teneur en vapeur d'eau
[Termes IGN] teneur intégrée en vapeur d'eauRésumé : (auteur) The vital role of water vapour in the Earth’s climate system requires measurements of the atmospheric Integrated Water Vapour (IWV) with a long-term stability and a high accuracy. This work focuses on using the Global Positioning System (GPS) to provide IWV estimates for climate applications. The advantages of the GPS measurements are that they can be performed independently on the weather and have a high temporal resolution (a few minutes) as well as a continuously improving spatial resolution (a few km for some local networks). The uncertainty of the GPS-derived IWV highly depends on the accuracy of the estimated Zenith Total Delay (ZTD), which is determined by many parameters, i.e. satellite orbit errors, ionospheric delay, signal multipath, antenna related errors (e.g. phase centre variations), and mapping functions. We demonstrated that the uncertainty of the GPS-derived IWV below 1 kg/m2 is achievable. The long-term change of the IWV can be an independent data source to detect climate changes. Using a global GPS IWV data set covering a 15-year-long time period, we found estimated IWV trends in a range from ¡1.65 to +2.32 kg/(m2¢decade) which, however, are comparable to the trend uncertainties varying from 0.21 to 1.52 kg/(m2¢decade). The trend uncertainty is mainly caused by the short-term variations of the IWV which cannot be modelled accurately. The uncertainty is also due to the errors in IWV estimates, which are random and/or elevation-dependent systematic errors. A higher elevation cutoff angle used in the GPS data analysis (a 25± was revealed for the time period investigated and for the region of Fennoscandia) can be an advantage to reduce the impact of such systematic errors. The GPS-derived IWV can also be used for the evaluation of climate models. The IWV derived from the GPS measurements acquired at 99 European sites, each with a maximum time series of 14 years, were compared to the IWV simulated by a regional climate model. Overall, a monthly mean difference of »0.5 kg/m2 (model¡GPS) is obtained where a significant seasonal variation is seen in the difference. The model is too dry in the summer. Study of the diurnal cycle of the IWV using both the GPS data and the model simulation shows a good agreement for the phase while a smaller amplitude is seen in the results from the model. Note de contenu : 1 Introduction
1.1 The role of water vapour in the climate system
1.2 Measurements of the atmospheric water vapour
1.3 Thesis structure
2 Measurement Techniques
2.1 Radiosonde
2.2 Radio techniques .
2.3 Summery of Paper A
3 Uncertainty Analysis of the IWV from GPS
3.1 Statistical analysis
3.2 Theoretical analysis
3.3 Summary of Paper B
4 GPS Meteorology for Climate Applications
4.1 Detection of climate changes using GPS data
4.2 Summary of Paper C
4.3 Evaluation of climate models using GPS data
4.4 Summary of Paper D
5 ConclusionsNuméro de notice : 14899 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Note de thèse : PhD : Earth and Space Sciences : Chalmers University of Technology, Sweden : 2012 DOI : sans En ligne : https://core.ac.uk/download/pdf/70594409.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76783 Documents numériques
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14899 Phd 2012 NingAdobe Acrobat PDF Interference & Einstein: GNSS update / Huibert-Jan Lekkerkerk in Geoinformatics, vol 15 n° 1 (01/01/2012)
[article]
Titre : Interference & Einstein: GNSS update Type de document : Article/Communication Auteurs : Huibert-Jan Lekkerkerk, Auteur Année de publication : 2012 Article en page(s) : pp 34 - 36 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement du signal
[Termes IGN] éruption solaire
[Termes IGN] interférence
[Termes IGN] navigation
[Termes IGN] signal GNSSRésumé : (Auteur) Some of you may have heard about the experiment at CERN that seems to prove that things can actually go faster than light, something that Einstein said was impossible. So what does a physical experiment have to do with a GNSS update you may ask. Numéro de notice : A2012-029 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31477
in Geoinformatics > vol 15 n° 1 (01/01/2012) . - pp 34 - 36[article]Réservation
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Titre : Système de positionnement intérieur basé sur des répéteurs de signaux GPS : utilisation de la phase et résolution des ambiguïtés Type de document : Mémoire Auteurs : T. Coupin, Auteur Editeur : Champs-sur-Marne : Ecole nationale des sciences géographiques ENSG Année de publication : 2012 Importance : 80 p. Format : 21 x 30 cm Note générale : Bibliographie
Rapport de stage de fin d'études, cycle des ingénieurs diplômés de l'ENSG 3ème année, [mastère spécialisé Photogrammétrie, Positionnement et Mesure de Déformation]Langues : Français (fre) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] ambiguïté entière
[Termes IGN] code GPS
[Termes IGN] filtre de Kalman
[Termes IGN] GNSS assisté pour la navigation
[Termes IGN] Matlab
[Termes IGN] mesurage de phase
[Termes IGN] méthode des moindres carrés
[Termes IGN] positionnement en intérieur
[Termes IGN] positionnement par GNSS
[Termes IGN] positionnement par GPS
[Termes IGN] pseudolite
[Termes IGN] résolution d'ambiguïté
[Termes IGN] signal GPS
[Termes IGN] trajet multipleIndex. décimale : MPPMD Mémoires du mastère spécialisé Photogrammétrie, Positionnement et Mesures de Déformation Résumé : (Auteur) A l'heure actuelle, le GPS est omniprésent dans notre société. De la navigation routière à la géodésie spatiale, le système de positionnement américain a fait ses preuves et s'est démocratisé, notamment avec la baisse du prix d'une puce de réception. La principale limitation du système est la réception des signaux émis par les satellites en orbite autour de la Terre. Les satellites émettent avec une puissance de 25 W et la puissance reçue à la surface est de l'ordre de 0.2 fW 2, autant dire rien du tout. Les signaux passent donc très mal au travers des murs et GPS devient inutilisable en intérieur. La communauté scientifique cherche donc à faire rentrer GPS dans les bâtiments et plusieurs solutions ont été proposées : les pseudolites et les répéteurs. Chacune présente avantages et inconvénients. Le département Électronique et Physique de Télécom SudParis a proposé lui un autre système combinant les avantages des pseudolites et répéteurs : les répélites. Le but de ce stage était d'étudier la possibilité d'utiliser la mesure de phase faite avec le système répélite et de fixer les ambiguïtés sur la mesure de phase. La fixation des ambiguïtés se déroule en 2 temps : l'estimation des ambiguïtés à une valeur réelle puis le passage à des ambiguïtés entières. Il s'avère que l'estimation est de meilleure qualité dès que le récepteur a un mouvement significatif par rapport au bruit de mesure. Ensuite la construction du système simplifie le passage aux valeurs entières puisqu'il suffit d'arrondir la valeur réelle à l'entier le plus proche et d'ajuster cette valeur en fonction d'autres paramètres propres au système. Note de contenu : Introduction
Comprendre le positionnement indoor
1. Introduction au positionnement indoor
1.1 Positionnent indoor non GNSS
1.2 Positionnent indoor à base de GNSS
2. État de l'art du positionnement par la phase
2.1 Utilisation d'un point connu
2.2 Mesure de synchronisation par une station de référence
2.3 Méthode de la station de référence non stationnaire
2.4 Bilan
3. Le système répélite
3.1 Le système
3.2 Le simulateur
Simulation sur le système répélite
4. Pré-traitement des mesures
4.1 Lissage des mesures de codes par les mesures de phases
4.2 Détection des multi-trajets
5. Estimation de la position et des ambiguïtés
5.1 Entrées et sorties de l'estimation
5.2 Contraintes pour le récepteur
6. Protocole de fixation des ambiguïtés
6.1 Comparaison des méthodes
6.2 Fixation des ambiguïtés
6.3 Test intensif du protocole
6.4 Fixation des ambiguïtés pour une trajectographie
Conclusion
Bibliographie
A. Filtre de Kalman
A.1 Prédiction
A.2 Mise à jour
B. Vue stéréoscopique de la surface de corrélation locale
C. Influence du point de départ
C.1 Récepteur fixe
C.2 Trajectoire circulaire
D. Influence du rayon de la trajectoire
D.1 Protocole
D.2 Résultats
E. Premiers essais du système répélite
E.1 Manipulations
E.2 Estimation de la trajectoire
F. Poster
G. Article
H. Annexes numériquesNuméro de notice : 20743 Affiliation des auteurs : ENSG (2012-2019) Thématique : POSITIONNEMENT Nature : Mémoire masters divers Organisme de stage : TELECOM SudParis Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=51150 Réservation
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20743_mem_ppmd_systeme_de_positionnement_interieur_coupin.pdfAdobe Acrobat PDF
Titre : Water vapor tomography using global navigation satellites systems Type de document : Thèse/HDR Auteurs : Donat Perler, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2012 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 84 Importance : 188 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-30-7 Note générale : Bibliographie
Doctoral ThesisLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] atmosphère terrestre
[Termes IGN] données GNSS
[Termes IGN] données météorologiques
[Termes IGN] modélisation spatiale
[Termes IGN] positionnement par GNSS
[Termes IGN] rayonnement électromagnétique
[Termes IGN] temps réel
[Termes IGN] teneur en vapeur d'eau
[Termes IGN] tomographie par GPS
[Termes IGN] vapeur d'eauIndex. décimale : 30.84 Applications de géodésie spatiale à l'atmosphère Résumé : (Auteur) Water vapor plays an important role in the atmosphere. It is involved in many atmospheric processes and is a major contributor to the atmospheric energy budget and as such is a key quantity in numerical weather prediction (NWP) models. In recent years, NWP models gain in importance in hazard mitigation. But to provide precise quantitative forecasts, especially with respect to precipitation, we need accurate knowledge of the water vapor distribution in the atmosphere. Ground-based Global Navigation Satellite System (GNSS) tomography is a technique which can provide highly resolved and accurate water vapor profiles in space and time.
The main objective of this thesis is to develop new tomographic algorithms which fulfill the requirements to assimilate refractivity measurements derived from GNSS into NWP models. A new tomography software called AWATOS 2 has been implemented. It is an assimilation system for point and integrated refractivity measurements. The tomographic model in AWATOS 2 is formulated as a Kalman filter and different voxel parameterizations are provided. The new trilinear and spline-based parameterizations allow a more accurate representation of the refractivity field without considerably increasing the number of unknowns. Advantages of these new parameterizations are a) more accurate results, b) point observations need not to be interpolated to the voxel centers and c) the tomographic solutions are at least C0-continuous in space. The stochastic prediction model implemented in AWATOS 2 relies on in-situ measurements and NWP model data. The prediction model is evaluated and adjusted with respect to data from the high-resolution NWP model COSMO-2 and from balloon soundings in Europe. In addition, AWATOS 2 provides a sophisticated simulation framework to carry out synthetic tests based on simple refractivity fields and on NWP model data. The algorithms of AWATOS 2 are assessed with synthetic tests and with real data in a longterm study using one year of data. The synthetic tests have confirmed the theoretical properties of the model such as a bias-free solution in case of bias-free input data, fast convergence rates, and the capability to resolve vertical structures in the wet refractivity field. In the long-term study, a root-mean-square (RMS) error of 3.0 ppm (0.4 gm3 absolute humidity) is achieved with respect to the NWP model COSMO-7. The investigations have shown that the newly introduced voxel parameterizations lead to significantly more accurate results than the classical constant parameterization.
The improvements are about 15% with respect to balloon soundings and 5% with respect to NWP analysis data. The performance of the trilinear and spline-based parameterizations are similar. Further investigations have revealed the importance of a bias correction model. A newly developed bias correction model has decreased the RMS error with respect to the NWP model analysis from 4.9 ppm (0.7 gm3) to 3.0 ppm (0.4 gm3) using the spline parameterization. For the other parameterizations, the improvements are significantly smaller. The systematic differences corrected here are mainly caused by a) systematic differences between GPS tropospheric path delays and the NWP model data and b) by discretization errors. Another error source is related to the departure of the NWP model’s topography from the true one which can amount to several hundred meters in alpine areas. Investigations have shown that processes near the Earth’s surface have a strong impact on the wet refractivity. Therefore, differences between the true topography and that of the NWP model can cause substantial errors. This topic has to be addressed if GNSS observations are assimilated into NWP models in complex terrain. Considerable progress has been made in the field of low-cost GNSS receivers in recent years allowing to build dense networks at low costs. Furthermore, the existing GNSSs are improved and new ones are being launched. These developments offer new possibilities in GNSS tomography. With error analyses, the potential of such improvements for GNSS tomography have been investigated The use of GPS together with Galileo has the potential to improve the formal accuracy of the GNSS tomography by 10-15% compared to a GPS-only solution. In Switzerland, equipping the SwissMetNet with GNSS receivers would increase the number of GNSS stations from 31 to 91. This would improve the formal accuracy of the tomographic solution by about 20-25%. The investigations have shown that the improvements obtained by a more dense network and additional GNSSs are cumulative. Placing the stations on different altitudes and choosing locations with good satellite visibility are important to achieve accurate results and should be considered in the design of GNSS networks.
All investigations have demonstrated that accurate 4D distributions of the wet refractivity in the troposphere can be estimated with GNSS tomography. The work has also revealed the possibilities and limitations of GNSS tomography in view of the assimilation into NWP models and proposes solution strategies to overcome the limitations.Note de contenu : 1 Introduction
1.1 Significance of tropospheric water vapor measurements
1.2 A short review of the research in GNSS tomography
1.3 Objectives and structure of the thesis
2 Introduction to the propagation of radio waves in the atmosphere
2.1 Propagation of radio waves in the atmosphere
2.2 Modeling the path delay
3 GNSS tomography with the software package AWATOS 2
3.1 Overview of AWATOS 2
3.2 Preprocessing of GNSS double difference delays
3.3 Discretization of the refractivity field and parameterization
3.4 Modeling the refractivity field with the Kalman filter approach
3.5 Simulation capabilities in AWATOS 2
4 Overview of the data sets
4.1 GPS data
4.2 Balloon soundings
4.3 Synoptic network SwissMetNet
4.4 Numerical weather prediction model COSMO
5 Description of the wet refractivity field
5.1 Tempo-spatial variation of the wet refractivity field
5.2 Discretization Error
5.3 Representation of the discretization error .
5.4 Investigations of the process noise using a random walk model
5.5 Conclusions
6 Comparison of balloon sounding data and GNSS-derived zenith path delays
6.1 Error budget of meteorological sensors
6.2 Intercomparison between zenith path delays of different sources
6.3 Conclusions
7 Potential of new GNSSs and dense networks in view of GNSS tomography
7.1 Configurations
7.2 Methods
7.3 Results and discussion
7.4 Conclusions
8 Simulation-based evaluation of the new tomographic algorithms
8.1 Theoretical considerations of the resolvability of vertical structures
8.2 Experiments with simulated data
8.3 Conclusions
9 Evaluation of the GPS tomography with a long-term study
9.1 Configuration and evaluation methods
9.2 Results and discussion
9.3 Bias correction model and its evaluation
9.4 Conclusions
10 Conclusions
11 OutlookNuméro de notice : 15546 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère DOI : 10.3929/ethz-a-006875504 En ligne : http://dx.doi.org/10.3929/ethz-a-006875504 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62758 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 15546-01 30.84 Livre Centre de documentation Géodésie Disponible Evaluation de l'érosion du site de Wankama (Niger) par comparaison de différents MNT / T. Gendre in XYZ, n° 129 (décembre - février 2011)PermalinkThe ionosphere : effects, GPS modeling and the benefits for space geodetic techniques / Manuel Hernández-Pajares in Journal of geodesy, vol 85 n° 12 (December 2011)PermalinkGLONASS modernization / Y. Urlichich in GPS world, vol 22 n° 11 (November 2011)PermalinkHigh-precision GNSS receivers / N. Blanco-Delgado in GIM international, vol 25 n° 11 (November 2011)PermalinkSpace-time equalization techniques for new GNSS signals / P. Anantharamu in GPS world, vol 22 n° 10 (October 2011)PermalinkInterpolating atmospheric water vapor delay by incorporating terrain elevation information / B. Xu in Journal of geodesy, vol 85 n° 9 (September 2011)PermalinkSimulation study of the influence of the ionospheric layer height in the thin layer ionospheric model / C. Brunini in Journal of geodesy, vol 85 n° 9 (September 2011)PermalinkStrapdown INS/DGPS airborne gravimetry tests in the Gulf of Mexico / X. Li in Journal of geodesy, vol 85 n° 9 (September 2011)PermalinkPermalink4D GPS water vapor tomography: new parameterized approaches / Donat Perler in Journal of geodesy, vol 85 n° 8 (August 2011)Permalink