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Titre : Publications 1994 [of the Delft geodetic computing centre] Type de document : Monographie Auteurs : Delft university of technology, Auteur Editeur : Delft [Pays-Bas] : Delft University of Technology Année de publication : 1995 Collection : LGR-SERIES num. 9 Importance : 378 p. Format : 21 x 30 cm Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale Index. décimale : 30.60 Géodésie spatiale Numéro de notice : 18211 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Recueil / ouvrage collectif Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=41441 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 18211-01 30.60 Livre Centre de documentation Géodésie Disponible A recursive procedure for computation and quality control of GPS differential corrections / X. Jin (1995)
Titre : A recursive procedure for computation and quality control of GPS differential corrections Type de document : Monographie Auteurs : X. Jin, Auteur Editeur : Delft [Pays-Bas] : Delft University of Technology Année de publication : 1995 Collection : LGR-SERIES num. 8 Importance : 83 p. Format : 21 x 30 cm Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] contrôle qualité
[Termes IGN] correction du signal
[Termes IGN] correction ionosphérique
[Termes IGN] erreur moyenne quadratique
[Termes IGN] erreur systématique
[Termes IGN] filtre de Kalman
[Termes IGN] GPS en mode différentiel
[Termes IGN] modèle ionosphérique
[Termes IGN] précision du positionnement
[Termes IGN] propagation ionosphérique
[Termes IGN] traitement de données GNSSIndex. décimale : 30.61 Systèmes de Positionnement par Satellites du GNSS Résumé : (Auteur) The DGPS technique can considerably improve the accuracy of stand-alone GPS positioning, since biases inherent in the latter technique are greatly reduced or even eliminated. But the improvement depends on the distance between the user and the reference station (spatial correlation), the latency of differential corrections (temporal correlation), and the quality of differential corrections. Therefore, how to correctly generate differential corrections is one of the keys to the DGPS positioning technique. Currently, there already exist several algorithms for the generation of differential corrections, for instance, the algorithm based on carrier filtered code observations and the algorithm based on code observations and sequential differences of carrier observations.
This research derives a new algorithm for generating differential corrections along with a recursive quality control procedure, which has some distinct features. First, it directly uses code and carrier observations in the measurement model of a Kalman filter, so that the measurements are not correlated in time if code and carrier observations can be assumed to have no time correlation. This makes it possible to use a simple stochastic observation model and to use the standard algorithm of the Kalman filter. Second, the algorithm accounts for biases like multipath errors and instrumental delays in code observations. It explicitly shows how code biases affect differential corrections when dual or single frequency data are used. Third, the algorithm can be easily integrated with a recursive quality control procedure, so that the quality of the estimated states can be guaranteed with certain probability. Fourth, in addition to the generation of differential corrections, it also produces the change of ionospheric delays and that of code biases with time. It can, therefore, be used to investigate properties of ionospheric delays and code biases. Finally, all state estimates including differential correction are not affected by the opposite influence of ionospheric delay on code and carrier observations.
On the basis of data collected by TurboRogue SNR-8000, Trimble 4000 SSE and Trirable 4000 SST receivers, this research also investigates the relationship between satellite elevation and the accuracy of code observations. Since this investigation uses code predicted residuals, which are dominated by code observation noises, the estimation of code observation accuracy is not affected by systematic errors caused by, for example, multipath and instrumental delays in code observations. It turns out that the deterioration of GPS code accuracy with decreasing elevation is very obvious at low elevation. When satellite elevation increases, the accuracy becomes more and more stable. The change of the code accuracy with satellite elevation can quite well be modelled by an exponential function of the form y=ao+a1.exp{-x/xo}, where y (the RMS error), ao and a1 have units of metres, and x (elevation) and xo are in degrees. For different types of receivers and different types of code observables, the parameters ao, a1 and xo may be different.
It is shown that by using code and carrier data with a sampling interval of one second, the dynamic behaviour of SA clock errors and that of ionospheric delays can well be modelled by quadratic and linear functions, respectively. The modelling accuracy is at least within a few millimetres.
Biases in code measurements are found and they may behave linearly and periodically with time. By using the same receiver, code biases related to different observation conditions have different behaviours and those related to the same satellite but observed in different frequencies (i.e. L1 and L2) may also not be the same.
Model testing experiments with simulated errors show that cycle slips as small as one cycle can be indeed successfully detected and identified in real time. The recursive quality control procedure allows for detection and identification of single as well as multiple model errors. But there exists a problem that the mean of the test statistic is always smaller than its expectation. It has been shown that this problem still remains after the relationship between satellite elevation and the accuracy of code observations is taken into account.
Based on the differential corrections generated by the new algorithm, it is shown that with increasing differential-correction latencies, the accuracy of differential-correction prediction decreases quadratically when SA clock errors are present and linearly when SA clock errors are absent. For latencies up to 5, 10 and 15 seconds, the accuracies are usually within 0.05, 0.2 and 0.5 in, respectively. Using differential-correction acceleration in differential-correction prediction can improve or worsen the accuracy when SA clock errors are present or absent, respectively. But the deteriorated accuracies related to satellites without SA clock errors are still better than the improved ones related to satellites with SA clock errors. For latencies within 15 seconds, the accuracy of differential-correction prediction can usually be reduced to below 0.2 metres if differential-correction accelerations are used.Numéro de notice : 18210 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=55351 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 18210-01 30.61 Livre Centre de documentation Géodésie Disponible Report on the geodetic activities in the years 1991 to 1995 presented to the XXI [21] General Assembly of the International Union of Geodesy and Geophysics in Boulder, Colorado, July 1995 / Commission géodésique suisse (1995)
Titre : Report on the geodetic activities in the years 1991 to 1995 presented to the XXI [21] General Assembly of the International Union of Geodesy and Geophysics in Boulder, Colorado, July 1995 Titre original : Rapport sur les travaux géodésiques exécutés de 1991 à 1995 présenté à la vingt-et-unième Assemblée générale de l'Union Géodésique et Géophysique Internationale tenue à Boulder, Colorado, juillet 1995 Type de document : Actes de congrès Auteurs : Commission géodésique suisse, Auteur ; Office fédéral de topographie (Suisse), Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 1995 Conférence : IUGG 1995, 21th general assembly, UGGI - IAG 02/07/1995 14/07/1995 Boulder Colorado - Etats-Unis Importance : 57 p. Format : 21 x 30 cm Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] activité géodésique
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] géodynamique
[Termes IGN] géopositionnement
[Termes IGN] Global Positioning System
[Termes IGN] gravimétrie
[Termes IGN] système de positionnement par satellites
[Termes IGN] technologies spatialesNuméro de notice : 18228 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Rapport Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=41449 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 18228-01 CG.95 Livre Centre de documentation Congrès Disponible
Titre : Satellitengeodätische Positionierung in der relativistischen Raum-Zeit Titre original : [Positionnement géodésique par satellites dans l'espace temps relatif] Type de document : Thèse/HDR Auteurs : V. Schwarze, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1995 Collection : DGK - C Sous-collection : Dissertationen num. 449 Importance : 125 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9492-5 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] correction du signal
[Termes IGN] espace-temps
[Termes IGN] ligne géodésique
[Termes IGN] mesurage de phase
[Termes IGN] propagation du signal
[Termes IGN] signal GPS
[Termes IGN] théorie de la relativitéIndex. décimale : 30.61 Systèmes de Positionnement par Satellites du GNSS Résumé : (Auteur) Satellite based positioning in curved space-time
Within this thesis we reformulate the observation equations for all commonly applied satellite based positioning systems within the framework of general relativity. Let us start with the representation of the space-time metric with respect to a geocentric, Earth-fixed chart. The definition of geodetic observables on a curved space-time manifold follows. For this purpose one introduces the so called observation frames which can be tied to coordinate induced frames by the matrix of integrating factors. An explicit form of the matrix of integrating factors is given.
Since each measurement process consists of transmitting and receiving of electromagnetic signals which are influenced by the presence of the gravitational field and of a refractive-dispersive medium we reformulate the relation between signal travel time and the spatial coordinate distance. It can be shown that the equation of motion of an electromagnetic wave leads to the differential equation of a geodesic line.
On the basis of the improved physical model described above we have to derive observation equations leading to the well known form spatial coordinate distance plus additional model quantities for all commonly applied observation techniques like the time-difference technique, the phase-difference technique and the integrated Doppler-count. We investigate the quantitative influence of the relativistic model terms. Numerical calculations concerning the signal propagation in a refractive and disperive medium as well as the adjustment of a GPS data-set conclude this thesis.Numéro de notice : 28040 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=63387 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 28040-01 30.61 Livre Centre de documentation Géodésie Disponible
Titre : Space geodesy techniques : an experimental and theoretical study of antenna sources Type de document : Monographie Auteurs : R.T.K. Jaldehag, Auteur Editeur : Göteborg [Suède] : Chalmers University of Technology Année de publication : 1995 Collection : Technical report num. 276 Importance : 100 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-91-7197-168-5 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] antenne
[Termes IGN] coin réflecteur
[Termes IGN] diffusion du rayonnement
[Termes IGN] Global Positioning System
[Termes IGN] interférométrie à très grande base
[Termes IGN] mesure de précision
[Termes IGN] positionnement par GPS
[Termes IGN] positionnement par ITGB
[Termes IGN] rebond post-glaciaire
[Termes IGN] réseau géodésique permanent
[Termes IGN] Suède
[Termes IGN] SWEPOS
[Termes IGN] système de positionnement par satellites
[Termes IGN] trajet multipleIndex. décimale : 30.00 Géodésie - généralités Résumé : (Auteur) This thesis presents work associated with antenna related error sources, as well as antenna design, in space geodesy utilizing the techniques of Very-Long-Baseline Interferometry (VLBI) and the Global Positioning System (GPS). Geodetic VLBI uses large ra-dio telescopes, often in global networks observing at least a few times per year. As the number of dedicated antennas for this purpose is limited, also antennas designed for radio astronomical research are used. However, new feed systems are needed to handle the si-multaneous dual-frequency observations and the large bandwidth in geodetic VLBI. This thesis describes and numerically evaluates such a feed system. The design has the advan-tage of not interfering with existing front-end receivers of traditional Cassegrain antennas. In contrast to VLBI antenna systems, GPS antennas have low directivity in order to receive signals from the satellites in different directions simultaneously. The disadvantage with such antennas is the relatively high susceptibility to scattering from structures close to the antenna. Two studies presented in this thesis show that signal scattering from structures associated with the mounting of the antenna to the pillar and with the pillar itself, might be a significant source of error. As nearby structures are in general located below the antenna, scattering from these structures may be minimized using antennas with reduced side- and back-lobe levels. This thesis presents results from a preliminary study of two new designs of such antennas. The Swedish permanent GPS network, SWEPOS, consists of 20 stations distributed across Sweden. One of the scientific motivations for this network is to monitor crustal motions associated with postglacial rebound. This thesis describes SWEPOS, and results from almost 18 months of daily observations are presented and compared to models of postglacial rebound. The results from SWEPOS have also uncovered two major error sources. One of them is the scattering effect mentioned above. The other, which also is investigated in this thesis, is related to snow accumulated on the top of the pillars and on the radomes that covers the antennas. This accumulation appears to refract and delay the GPS signals, and thus degrade the positioning accuracy. Note de contenu : Preface
PART 1
Chapter 1 Introduction
1.1 Space Geodesy Techniques
1.2 Global Geodynamics
Chapter 2 Geodetic Very-Long-Baseline Interferometry
2.1 Background
2.2 The Main Principles
2.3 Antennas and Feeds
Chapter 3 The Global Positioning System
3.1 Background
3.2 The Main Principles
3.3 Relative Positioning Using the Carrier Phase Observables
3.4 Error Sources
3.4.1 Satellite and Receiver Clocks
3.4.2 Satellite Orbits
3.4.3 Atmospheric Delay
3.4.4 Antenna Related Effects
Chapter 4 Summary and Main Points of Thesis Papers
4.1 Main Points of Paper A
4.2 Main Points of Paper B
4.3 Main Points of Paper C
4.4 Main Points of Paper D
4.5 Main Points of Paper E
4.6 Main Points of Paper F
References
PART 2
Paper A
Paper B
Paper C
Paper D
Paper E
Paper FNuméro de notice : 18238 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=55358 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 18238-01 30.00 Livre Centre de documentation Géodésie Disponible PermalinkPermalinkTraitements des observations de géodésie sur satellites (mars 1994, rév. octobre 1995) / Henri Duquenne (1995)
PermalinkPermalinkAtmospheric pressure loading effects on global positioning system coordinate determinations / Tonie M. VanDam in Journal of geophysical research : Solid Earth, vol 99 n° 12 (10/12/1994)
Permalinkvol 5 n° 11 - November 1994 (Bulletin de GPS world)
Permalinkvol 5 n° 10 - October 1994 (Bulletin de GPS world)
Permalinkvol 5 n° 9 - September 1994 (Bulletin de GPS world)
PermalinkThe contribution of the DORIS system to the global terrestrial reference frame / Pascal Willis (01/09/1994)
Permalinkvol 5 n° 7 - July 1994 (Bulletin de GPS world)
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