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Improving the precision and accuracy of geodetic GPS / A. Bilich (2006)
Titre : Improving the precision and accuracy of geodetic GPS : applications to multipath and seismology Type de document : Thèse/HDR Auteurs : A. Bilich, Auteur ; K. Larson, Directeur de thèse Editeur : Boulder [Etats-Unis] : University of Colorado Année de publication : 2006 Importance : 374 p. Format : 21 x 28 cm ISBN/ISSN/EAN : 978-0-542-94205-1 Note générale : Bibliographie
A thesis submitted to the Faculty of the graduate school of the University of Colorado in partial fulfillment of the requirements for the degree of Doctor of philosophy, department of aerospace engineering sciencesLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] égalisation
[Termes IGN] erreur de positionnement
[Termes IGN] filtrage du bruit
[Termes IGN] mesurage de phase
[Termes IGN] mesurage de pseudo-distance
[Termes IGN] positionnement par GPS
[Termes IGN] rapport signal sur bruit
[Termes IGN] réduction
[Termes IGN] séisme
[Termes IGN] sismologie
[Termes IGN] trajet multipleIndex. décimale : THESE Thèses et HDR Résumé : (Auteur) The Global Positioning System (GPS) enables precise and accurate determination of position anywhere on anywhere on the Earth, a boon to the field of geodesy. Although great advances in geodetic GPS positioning precision and accuracy have been made over the last decade, improvements can still be made. This dissertation addresses GPS positioning error from two different directions---understanding and taking advantage of the repeating nature of some errors, or understanding and taking advantage of the relationship between errors in different contemporaneous GPS observables. In the area of high-rate GPS positioning, repeating errors have a substantial impact on the solution. In this dissertation, I study high-rate GPS error reduction using data from the 2002 Denali Fault earthquake. I apply the techniques of modified sidereal filtering and spatial filtering to positions from 25 GPS stations throughout northwestern North America, and I develop improvements to these methods such as data equalization and careful selection of sidereal filtering sites. Substantial reduction in noise magnitude is achieved through proper application of sidereal and spatial filters, and the resulting 'GPS seismograms' show excellent agreement to records from seismometers. Multipath, where GPS signals arrive by more than one path and thereby create a range error, can be understood through the GPS observables. Multipath effects on GPS carrier phase, pseudorange, and signal-to-noise ratio (SNR) measurements are different but linked by the same underlying principles. In this dissertation, I explain multipath effects on the GPS observables and define multipath in terms of conditions specific to geodetic GPS installations and receivers. I develop two approaches to multipath errors, both using SNR measurements---a graphical method for multipath assessment, and a computational method for multipath modeling and carrier phase error reduction. The graphical method shows great promise for understanding spatial and temporal variability in multipath errors, but provides no avenue for removing these errors. The theory behind SNR modeling is robust, but complicated to implement with geodetic GPS measurements of SNR. I discuss the difficulties inherent in SNR modeling and demonstrate how this technique is of limited utility for geodetic GPS even in the most simple of multipath environments. Note de contenu : 1 Introduction
1.1 Global Positioning System Background
1.2 GPS Observables
1.3 Position Estimation with GIPSY
1.3.1 Satellite Orbits
1.3.2 Earth and Observation Models
1.3.3 Removing Ionospheric Effects
1.3.4 Unmodeled Terms
1.3.5 Position Solution
2 Overview of High-Rate Positioning Research
2.1 Comparision of GPS and Seismologic Measurements
2.2 Previous Work in GPS Seismology
2.3 Case Study: 2002 November 3 Denali Fault Event
2.3.1 Denali Fault earthquake
2.3.2 GPS network and analysis
2.3.3 Error-reduction methodology
3 High-rate GPS Techniques
3.1 Sidereal Filtering
3.1.1 Orbital repeat period
3.1.2 Modified sidereal filtering (MSF) method
3.1.3 Variables in sidereal filtering process
3.2 Additional Data Analysis
3.2.1 Ambiguity resolution
3.2.2 Data editing
3.3 Spatial Filtering
3.3.1 Common-mode errors
3.3.2 Spatial filtering method
3.3.3 Spatial filtering sites
3.3.4 Role of the reference site and filter order
4 High-rate GPS Results and Discussion
4.1 Surface Waves Recorded by GPS
4.2 Positioning Noise
4.2.1 Noise floor of GPS receivers
4.2.2 Generalized noise in GPS positions
4.3 Comparison to Seismic Recordings
4.4 Summary and Conclusions
4.5 Future Work
5 Overview of Multipath Research
5.1 Previous Work
5.2 Research Motivation and Overview
6 Principles of Multipath and SNR
6.1 GPS Receiver Signal Tracking
6.2 Multipath Terminology
6.3 Multipath Effects on GPS Observables
6.3.1 Pseudorange multipath
6.3.2 Carrier phase multipath
6.3.3 Effect of multipath on SNR
6.4 Summary of Multipath Theory
7 Multipath Under Geodetic GPS Conditions
7.1 Multipath Geometry for the Geodetic Case
7.1.1 Multipath geometry and errors
7.1.2 Time-varying behavior of ø and SNR
7.1.3 Multipath geometry and periodicity
7.1.4 Resolvable multipath frequencies
7.1.5 Multipath phasor spin
7.1.6 Direct and multipath amplitudes
7.1.7 Summary
7.2 Geodetic GPS Receivers
7.2.1 Computation and reporting of SNR
7.2.2 Characteristics of geodetic GPS SNR
7.2.3 Correlation of SNR and pseudorange multipath
7.2.4 Conclusions
8 Multipath Assessment for Permanent GPS Stations
8.1 SNR Power Spectral Maps
8.1.1 Spectral power estimates
8.1.2 Representation of gridded spectral power
8.2 Examples of Power Spectral Maps
8.2.1 TASH: tall pillar
8.2.2 MKEA: reflections from angled surfaces
8.2.3 CHUR: variable topography
8.3 Discussion and Future Work
9 Estimation of SNR-based Multipath Corrections
9.1 Direct Signal Amplitude and SNR Due to Multipath
9.2 Signal Conditioning
9.3 Multipath Frequency Estimation Via Sliding-Window Fast Fourier Transform (SWFFT)
9.4 Amplitude and Multipath Phase Estimation Via Adaptive Least Squares (ALS)
9.5 Construction of SNR and Multipath Corrections
9.6 Simulations
10 Phase Multipath Mitigation for GPS Stations
10.1 Salar de Uyuni Experiment
10.1.1 Phase errors
10.1.2 Phase multipath corrections
10.1.3 Effect of corrections on residuals and positions
10.2 TASH/KIT3 Network
10.2.1 SNR data
10.2.2 Phase multipath corrections
10.2.3 Phase errors and corrections
10.3 Discussion and Future Work
11 ConclusionsNuméro de notice : 14325 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse française Note de thèse : Thèse de doctorat : philosophy. department of aerospace engineering sciences : Boulder,University of Colorado : 2006 nature-HAL : Thèse DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=45244 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 14325-01 THESE Livre Centre de documentation Thèses Disponible Precise relative positioning of formation flying spacecraft using GPS / R. Kroes (2006)
Titre : Precise relative positioning of formation flying spacecraft using GPS Type de document : Monographie Auteurs : R. Kroes, Auteur Editeur : Delft : Netherlands Geodetic Commission NGC Année de publication : 2006 Collection : Netherlands Geodetic Commission Publications on Geodesy, ISSN 0165-1706 num. 61 Importance : 163 p. Format : 17 x 24 cm ISBN/ISSN/EAN : 978-90-6132-296-2 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] ambiguïté entière
[Termes IGN] compensation Lambda
[Termes IGN] erreur systématique
[Termes IGN] filtre de Kalman
[Termes IGN] GPS-INS
[Termes IGN] GRACE
[Termes IGN] image TerraSAR-X
[Termes IGN] mesurage de pseudo-distance
[Termes IGN] méthode des moindres carrés
[Termes IGN] navigation spatiale
[Termes IGN] orbitographie par GNSS
[Termes IGN] positionnement différentiel
[Termes IGN] positionnement par GPS
[Termes IGN] précision millimétrique
[Termes IGN] qualité des données
[Termes IGN] résolution d'ambiguïté
[Termes IGN] signal GPSIndex. décimale : 30.70 Navigation et positionnement Résumé : (Auteur) Spacecraft formation flying is currently considered as a key technology for advanced space missions. Compared to large individual spacecraft, the distribution of Sensor systems amongst multiple platforms offers improved flexibility and redundancy, shorter times to mission and the prospect of being more cost effective. Besides these advantages, satellite formations in low Earth orbit provide advanced science opportunities that cannot, or not easily, be realized with single spacecraft. One of the fundamental issues of spacecraft formation flying is the determination of the relative state (position and velocity) between the satellite vehicles within the formation. Knowledge of these relative states in (near) real-time is important for operational aspects. In addition, some of the scientific applications, such as high resolution interferometry, require an accurate post-facto knowledge of these States. The goal of this dissertation is therefore to develop, implement and test a method for high precise post-facto relative positioning of formation flying spacecraft, using GPS observation data. The need for such a methodology comes from scientific satellite formation flying missions that are currently being planned. A good example here is the Synthetic Aperture Radar (SAR) interferometry formation consisting of the TerraSAR-X and TanDEM-X satellites. The primary mission objective here requires the relative position to be known within a 2 mm precision (1-dimensional).
GPS receivers are often considered as the primary instruments for precise relative navigation in future satellite formation flying missions. As is commonly known, precise relative positioning between GPS receivers in geodetic networks is exercised on a routine basis. Furthermore, GPS receivers are already frequently used onboard satellites to perform all kinds of navigational tasks, are suitable for real-time applications and provide measurements with a 3-dimensional nature.
Previous studies carried out in this research area focussed on the real-time or operational aspects, and all used GPS data obtained from software or hardware-in-the-loop simulations. This dissertation clearly distinguishes itself due to the fact that the developed methodology has been tested using real-world GPS data from the GRACE mission, which in addition also provides a precise way to validate the obtained results by means of the GRACE K/Ka-Band Ranging System (KBR) observations.
One of the key aspects of any GPS positioning application is the quality of the observation data used. To this extent an in-flight performance analysis of the used GRACE (and CHAMP) GPS data bas been carried out. The results show that the GRACE GPS pseudorange observations, on the individual frequencies, are subject to systematic errors in the order of 10-15 cm. Furthermore, an assessment of the noise of both the GPS pseudorange and carrier phase data demonstrates that the noise of the GRACE B observation data is significantly lower.
When using GPS for precise relative spacecraft positioning, the trajectory or orbit of one of the spacecraft, serving as the reference, has to be known to the best possible extent. In order to facilitate this, a total of three precise orbit determination strategies, using undifferenced ionosphere free GPS pseudorange and carrier phase observations, have been implemented and tested. They comprise a kinematic and reduced dynamic batch LSQ estimation method, as well as an extended Kalman filter/smoother (EKF), that also form the conceptual basis for the relative spacecraft positioning strategies. Each of the precise orbit determination concepts has been tested using GPS data from the CHAMP and GRACE missions. The reduced dynamic batch LSQ orbits were validated with Satellite Laser Ranging data, where the residuals showed an RMS of 3-4 cm.
Out of a total of four possible processing strategies that have been identified for relative spacecraft positioning, only an extended Kalman filter/smoother has proven to work satisfactorily when tested on the real-world GRACE GPS data. The EKF processes single difference GPS pseudorange and carrier phase observations and uses (pseudo) relative spacecraft dynamics to propagate the relative satellite state over the observation epochs. Despite its single difference parametrization the EKF can still resolve and incorporate the integer double difference carrier phase ambiguities, which is commonly regarded as, and has proven to be in this dissertation, the key to precise GPS based relative positioning. Estimation of the integer ambiguities is accomplished by the well known Least Squares Ambiguity Decorrelation Adjustment (LAMBDA) method. Due to the presence of systematic errors in the GRACE GPS data, a relatively conservative validation of the estimated integer ambiguity parameters was found to be required prior to their incorporation in the filter. When validating the daily ambiguity fixed GRACE relative position solutions from the EKF with the KBR observations, it has been shown that an actual overall relative position precision of 0.9 mm (1-dimensional) over a 101 day data arc is achieved. This dissertation is the first that proves that such precision can be truly obtained for real-world relative spacecraft positioning applications.Note de contenu : Acknowledgements
Important Acronyms
Summary
Samenvatting (Summary in Dutch)
1 Introduction
1,1 Spacecraft formation flying using GPS
1.2 Research objective and motivation
1.3 The CHAMP and GRACE satellite missions
1.4 Outline
2 GPS observations
2.1 Observation types
2.3 Linear data combinations
2.4 Linearization for positioning
2.5 Relative positioning models
2.6 GPS data quality
3 Precise orbit determination
3.1 GPS orbit and clock products
3.2 Reference frame transformations.
3.3 Kinematic orbit determination.
3.4 Reduced dynamic orbit determination
3.5 GHOST toolkit
3.6 POD results
4 Relative spacecraft positioning
4.1 Integer ambiguity resolution
4.2 Proposed processing strategies
4.3 Details of the extended Kalman filter
4.4 Extended Kalman filter results.
4.5 Some words on
5 Conclusions and outlook
A Integer Ambiguity Estimation
B Lower boundary for the bootstrapping success rate
BibliographyNuméro de notice : 15179 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=55089 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 15179-01 30.70 Livre Centre de documentation Géodésie Disponible 15179-02 30.70 Livre Centre de documentation Géodésie Disponible Le point sur les traitements de données GNSS en réseau pour un positionnement centimétrique temps réel de meilleure qualité / Romain Legros in XYZ, n° 105 (décembre 2005 - février 2006)
[article]
Titre : Le point sur les traitements de données GNSS en réseau pour un positionnement centimétrique temps réel de meilleure qualité Type de document : Article/Communication Auteurs : Romain Legros, Auteur ; F. Molle, Auteur ; N. Balard, Auteur Année de publication : 2005 Article en page(s) : pp 51 - 58 Note générale : Bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] ambiguïté entière
[Termes IGN] double différence
[Termes IGN] interpolation
[Termes IGN] perturbation ionosphérique
[Termes IGN] positionnement par GNSS
[Termes IGN] positionnement par GPS
[Termes IGN] précision centimétrique
[Termes IGN] réfraction atmosphérique
[Termes IGN] temps réel
[Termes IGN] traitement de données GNSSRésumé : (Auteur) Depuis les années 80 et la mise en place du système GPS, les recherches dans le domaine du radiopositionnement par méthodes GNSS n'ont cessé de s'étendre et il est aujourd'hui possible de se positionner en temps réel avec une précision centimétrique de manière totalement transparente en traitant les données d'observation en réseau, afin de résoudre de manière satisfaisante la majorité des problèmes rencontrés en mode RTX. D'une manière générale, il s'agit de modéliser les erreurs spatialement corrélées (ionosphère, troposphère et éphémérides) sur chaque station avant de mettre en place des modèles de propagation en réseau (plans, polynômes ou modèles d'interpolation plus ou moins complexes) et de diffuser les données nécessaires aux utilisateurs (corrections et/ou observations) pour qu'ils puissent se positionner par double différence avec la précision escomptée suivant diverses approches. L'enjeu est de taille puisqu'il s'agit, au moment où plusieurs réseaux sont en passe de couvrir le territoire (ORPHEON, TERIA, etc.), de démocratiser l'utilisation de l'information géographique en favorisant son accès. Numéro de notice : A2005-485 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27621
in XYZ > n° 105 (décembre 2005 - février 2006) . - pp 51 - 58[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 112-05041 RAB Revue Centre de documentation En réserve L003 Exclu du prêt Analyse des stochastischen Modells von GPS-Trägerphasenbeobachtungen / J. Howind (2005)
Titre : Analyse des stochastischen Modells von GPS-Trägerphasenbeobachtungen Titre original : [Analyse de modèles stochastiques des observations de phase GPS] Type de document : Thèse/HDR Auteurs : J. Howind, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2005 Collection : DGK - C Sous-collection : Dissertationen num. 584 Importance : 103 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-5023-5 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] base géodésique
[Termes IGN] covariance
[Termes IGN] données GPS
[Termes IGN] double différence
[Termes IGN] hauteur ellipsoïdale
[Termes IGN] matrice de covariance
[Termes IGN] méthode des moindres carrés
[Termes IGN] modèle stochastique
[Termes IGN] phase GPS
[Termes IGN] précision du positionnement
[Termes IGN] résidu
[Termes IGN] série temporelle
[Termes IGN] traitement de données GNSSIndex. décimale : 30.61 Systèmes de Positionnement par Satellites du GNSS Résumé : (Auteur) Geodetic observations are usually processed by means of the Least Squares Method. However, this algorithm delivers reliable valuations of unknown parameters und associated accuracy measures only if the functional and stochastic models are appropriate. Observations using the Global Positioning System (GPS) are affected by various influences, e.g. by the atmosphere. Hence, it seems to be a reasonable conclusion that the commonly used stochastic model of GPS-observations with a scaled identity matrix with homoscedastic (i.e. equal variance) and uncorrelated errors is not adequate. The knowledge of the stochastic behaviour of GPS-observations can be improved by analyzing time series of residuals originating from Least Squares evaluation. Based on this analysis a procedure for modifying the covariance matrix of double-differenced GPS carrier-phase observations is presented. Essentially, it consists of two steps. At first individual variance functions for all double-difference observations depending on the satellite elevation for modifying the main diagonal of its covariance matrix are estimated. Secondly, temporal correlations are determined to adapt the other parts of the covariance matrix. All steps are verified by suitable statistical tests. The procedure is applied to extensive data sets with different characteristics. The results of the evaluation process, taking into account all realizations of the stochastic model mentioned above, are presented. It is shown that modifying the main diagonal of the covariance matrix with elevation-dependent variance functions leads to significant changes in the estimated ellipsoidal height of GPS-stations only for long baselines. The accuracy measures are not affected by this modification. In contrast to these results, considering temporal correlations in the covariance matrix of GPS-double difference observations causes distinct changes in the accuracy measures of all coordinate components independently of the baseline length. Numéro de notice : 13272 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54951 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 13272-01 30.61 Livre Centre de documentation Géodésie Disponible 13272-02 30.61 Livre Centre de documentation Géodésie Disponible Spacecraft formation flying: relative positioning using dual-frequency carrier phase / R. Kroes in GPS world, vol 15 n° 7 (July 2004)
[article]
Titre : Spacecraft formation flying: relative positioning using dual-frequency carrier phase Type de document : Article/Communication Auteurs : R. Kroes, Auteur ; Oliver Montenbruck, Auteur Année de publication : 2004 Article en page(s) : pp 37 - 42 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] GPS en mode cinématique
[Termes IGN] GPS en mode différentiel
[Termes IGN] mesurage de pseudo-distance
[Termes IGN] phase GPS
[Termes IGN] positionnement différentiel
[Termes IGN] récepteur bifréquenceRésumé : (Auteur) On July 16, 1982, a Delta launch vehicle propelled the Landsat-4 remote sensing satellite into orbit. This satellite, the fourth in the United States' Landsat program, carried a new suite of sensors which produced data of such detail and clarity that its use represented a major advance in Earth observations from space. In addition, Landsat-4 carried the first GPS receiver into orbit. Although only a few of the prototype Block I GIPS satellites were available at the time, Landsat-4's GPS receiver demonstrated that a spacecraft could be navigated with GPS to an accuracy better than 50 meters. Since that inaugural flight, dozens of GPS receivers have flown in space.These receivers have not only provided accurate positions and velocities of their host spacecraft but also determined spacecraft attitude and accurate time for spacecraft sensors, and profiled the atmosphere by observing GPS satellites as they are occulted by the Earth's limb. In this month's column, we look at yet another application of GPS in space : precisely determining the relative positions of cooperative spacecraft flying in formation. Simultaneous measurements by multiple formation-flying satellites can provide significant benefits to a wide variety of space missions. Such measurements can yield higher-resolution imagery and interferometry or information on small-scale spatial variations in atmospheric properties or gravity. The concept can also be extended to provide robust and redundant fault-tolerant spacecraft system architectures and complex networks dispersed over clusters of satellites. Some of these applications require knowing the precise location of each cooperating spacecraft. Dual-frequency GPS carrier-phase observations can provide the required precision. Numéro de notice : A2004-597 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27113
in GPS world > vol 15 n° 7 (July 2004) . - pp 37 - 42[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 067-04071 SL Revue Centre de documentation Revues en salle Disponible Navigation for precision approaches: robust integrity monitoring using GPS + Galileo / P. Misra in GPS world, vol 15 n° 4 (April 2004)PermalinkGPS satellite surveying / Alfred Leick (2004)PermalinkPhase ambiguity determination for the positioning of interferometric SAR data / A. Sowter in Photogrammetric record, vol 18 n° 104 (December 2003 - February 2004)PermalinkStatistische Untersuchung ganzzahliger und reellwertiger unbekannter Parameter im GPS-Modell / B. Gundlich (2002)PermalinkGeodetic applications of the global navigation satellite system (GLONASS) and of GLONASS-GPS combinations / H. Habrich (2000)PermalinkZur Entwicklung eines GPS-Programmsystems für Lehre und Tests unter besonderer Berücksichtigung der Ambiguity Function Methode / B. Zebhauser (2000)PermalinkGlobal Positioning System, papers published in Navigation, volume 5 / Institute of navigation (1998)PermalinkRecursive data processing for kinematic GPS surveying / Christian Tiberius (1998)PermalinkPermalinkNew GPS measurement modeling techniques of orbit determination and precise kinematic positioning / M. Yang (1995)Permalink