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Titre : High precision GPS processing in kinematic mode Type de document : Monographie Auteurs : Marc Cocard, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 1995 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 52 Importance : 140 p. Format : 21 x 30 cm Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] ambiguïté entière
[Termes IGN] données GPS
[Termes IGN] GPS en mode cinématique
[Termes IGN] mesurage de pseudo-distance
[Termes IGN] orbitographie
[Termes IGN] résolution d'ambiguïté
[Termes IGN] traitement de données GNSSIndex. décimale : 30.61 Systèmes de Positionnement par Satellites du GNSS Résumé : (Auteur) This report deals with the calculation of highly accurate trajectories of moving vehicles, and of air planes in particular, from differential GPS measurements processed in the offline mode.
In the last few years the Global Positioning System (GPS) has become the most powerful navigation system worldwide. Although it was developed by the American Department of Defense (DoD) and is, therefore, primarily designated for military use, the number of civilian users is rapidly increasing from day to day. Based on satellite measurements, GPS allows instantaneous positioning accurate to within 100200 meters. [Remondi, 1984] bas shown that differential processing of phase measurements allows improvement of position accuracy to few centimeters. There are numerous applications for spatial trajectories calculated with such high quality accuracy: e.g. their integration in photogrammetric aerotriangulation allows considerable reduction of the number of control points on the ground. Also in airborne gravimetry new horizons are being opened by using GPS.
A software system for processing kinematic data in the offline mode has been developed. Its key features are presented first. A robust and flexible approach using simultaneously phase and codemeasurements in a differential way is used. For the computation the differences between the code and phase information, measured by the roving receiver as well as by a fixed reference receiver, are used in order to reduce the systematic errors, which affect both receivers in a similar way. The main differences between the phase and the code data are (a) noise (decimeters to meters for the code, millimeters for the phase) and (b) the unknown ambiguities in the phase measurements, which are known to be integer values. Processing is carried out in two steps: firstly a least squares adjustment is applied in order to determine the timeinvariant parameters, using the entire data set. Parameters which are considered as invariant are the ambiguities and the coordinates of the roving receiver during stationary periods. Next, the integer values of the ambiguities are determined. In a second step the trajectory is reprocessed by introducing the known ambiguities.
The key problem in obtaining highaccuracy trajectories consists in making reliable identification of the integervalued ambiguities. It is demonstrated that a conventional sigma dependent rounding strategy, commonly used in static applications, is still a useful tool in offline kinematic processing. In addition, a more powerful search strategy has been analyzed and simulations show that under ideal conditions the integer values of the ambiguities can be retrieved within one epoch worth of dualfrequency measurements. These simulated results have been validated by real data. With increasing distance between the roving and the reference receiver a stochastic modelling of the ionospheric path delay gave good results but also showed the limitation of instantaneous ambiguity resolution.
Using GPS data of good quality trajectories with an accuracy of a few centimeters were recovered. With increasing distance between rover and reference station (up to 100 kilometers), however, all ambiguities could not always be resolved and the quality of the resulting trajectories deteriorates to some decimeters. But even in this case it was possible to derive the velocity and acceleration of the aircraft with high accuracy from the coordinates.Numéro de notice : 12607 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Monographie En ligne : https://www.sgc.ethz.ch/sgc-volumes/sgk-52.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54706 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 12607-01 30.61 Livre Centre de documentation Géodésie Disponible 12607-02 30.61 Livre Centre de documentation Géodésie Disponible Practical experience with GPS supported aerial triangulation : paper read at the one-day symposium of the society, entitled GPS and photogrammetry on 1st November 1993 / F. Ackermann in Photogrammetric record, vol 14 n° 84 (October 1994 - March 1995)
[article]
Titre : Practical experience with GPS supported aerial triangulation : paper read at the one-day symposium of the society, entitled GPS and photogrammetry on 1st November 1993 Type de document : Article/Communication Auteurs : F. Ackermann, Auteur Année de publication : 1994 Article en page(s) : pp 861 - 874 Note générale : Bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Photogrammétrie analytique
[Termes IGN] aérotriangulation
[Termes IGN] compensation par bloc
[Termes IGN] point d'appui
[Termes IGN] point de vérification
[Termes IGN] positionnement par GPS
[Termes IGN] résolution d'ambiguïté
[Termes IGN] véhicule aérienRésumé : (Auteur) The operational situation of precise airborne GPS positioning of camera air stations and its use in combined block adjustment for aerial triangulation is reviewed. The acceptance of systematic GPS errors, which occur especially with biased phase ambiguity solutions after loss of lock of signals in-flight, has motivated the method of additional linear GPS drift parameters which are to be solved in the combined block adjutment. It also implies that no absolute GPS coordinates are required and that the datum transformation is provided via a few ground control points. A great number of practical examples demonstrates that the method has been successfully applied within a wide range of photoscales and of block sizes. It has proved to be fully operational under various pratical conditions. The high accuracy performance of GPS blocks and the economic benefit have been confirmed. It is particularly noticeable that the stationary receiver can be at a great distance, up to 500 km or more from the mission area. The conclusion is drawn that GPS supported aerial triangulation is ready to become standard. The potential improvement from dual frequency receivers and fast ambiguity solutions only enhances that conclusion. Numéro de notice : A1994-026 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/j.1477-9730.1994.tb00287.x En ligne : https://doi.org/10.1111/j.1477-9730.1994.tb00287.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=25730
in Photogrammetric record > vol 14 n° 84 (October 1994 - March 1995) . - pp 861 - 874[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 106-94022 RAB Revue Centre de documentation En réserve L003 Disponible 106-94021 RAB Revue Centre de documentation En réserve L003 Disponible Dynamic GPS height determination in the decimeter level for bathymetric applications / Robert Lemmens (1993)
Titre : Dynamic GPS height determination in the decimeter level for bathymetric applications Type de document : Monographie Auteurs : Robert Lemmens, Auteur Editeur : Delft [Pays-Bas] : Delft University of Technology Année de publication : 1993 Collection : LGR-SERIES num. 4 Importance : 110 p. Format : 21 x 30 cm Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] bathymétrie
[Termes IGN] GPS en mode différentiel
[Termes IGN] positionnement différentiel
[Termes IGN] positionnement dynamique
[Termes IGN] précision décimétrique
[Termes IGN] propagation ionosphérique
[Termes IGN] résolution d'ambiguïté
[Termes IGN] synchronisation
[Termes IGN] temps réel
[Termes IGN] trajet multipleIndex. décimale : 30.70 Navigation et positionnement Résumé : (Auteur) This research treats the feasibility of using GPS for accurate height determination of the echo sounder transducer in bathymetric applications. Positioning should be possible in the decimeter level after proper resolution of the carrier phase integer cycle ambiguity. On-the-fly ambiguity resolution techniques are used to accomplish this in a dynamic environment. To test dynamic GPS relative positioning performance, a short-baseline experiment was carried out with a wave simulator which produced an accurate reference trajectory. Using L1 carrier phase observations and C/A-code observations with a 7-satellite configuration, heights in the centimeter level were achieved after an initialization period of a few minutes. Several parts of the experiment show the importance of redundant satellites and the vulnerability of the ambiguity resolution to periodic errors and cycle slips. Dynamics in height direction of 10 cm/s do not seem to affect the ambiguity resolution process, but increase the noise level of the resulting positions. In practice baselines of a few tens of kilometers also need knowledge of atmospheric delays. Assuming these effects are well modeled, which seems feasible at the moment, and multipath is reduced, height determination is possible with an accuracy of about one decimeter for baselines of a few tens of kilometers and 1-2 decimeter for longer baselines. A high confidence level of the positions can be obtained by thorough quality control, as can be achieved by statistical testing on cycle slips and outliers. The reliability of the system will be increased by several redundant observations like simultaneously measuring 7 or more satellites, multiple reference stations, using an external timebase, etc. Finally to explore full GPS accuracy in the bathymetric survey, aspects of integrating GPS, the echo sounder and additional measurements are considered. Although relative GPS heights as obtained in this research are very well applicable in several survey applications, the decimeter accuracy of absolute heights seems still difficult to achieve when these heights are needed with respect to an absolute levelling datum, because the local relation between the levelling datum and the WGS84 ellipsoid is often not well known. Other aspects like sensor offset and time synchronization also appear to be important when integrating GPS in a bathymetric surveying system. Numéro de notice : 18207 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=55349 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 18207-01 30.70 Livre Centre de documentation Géodésie Disponible GPS-Verfahren für den Nahbereich mit kurzen Beobachtungszeiten in Vermessung und Ortung / K. Sauermann (1993)
Titre : GPS-Verfahren für den Nahbereich mit kurzen Beobachtungszeiten in Vermessung und Ortung Titre original : [Procédés GPS pour une zone proche avec un court temps d'observation dans la mesure et la détection] Type de document : Thèse/HDR Auteurs : K. Sauermann, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1993 Collection : DGK - C Sous-collection : Dissertationen num. 403 Importance : 146 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9448-2 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] centre de phase
[Termes IGN] compensation
[Termes IGN] correction atmosphérique
[Termes IGN] données GPS
[Termes IGN] double différence
[Termes IGN] GPS en mode cinématique
[Termes IGN] GPS en mode différentiel
[Termes IGN] mesurage de phase
[Termes IGN] résolution d'ambiguïté
[Termes IGN] simple différence
[Termes IGN] triple différenceIndex. décimale : 30.61 Systèmes de Positionnement par Satellites du GNSS Numéro de notice : 28080 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=63427 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 28080-01 30.61 Livre Centre de documentation Géodésie Disponible 28080-02 30.61 Livre Centre de documentation Géodésie Disponible The lambda method for integer ambiguity estimation / P.J. de Jonge (1993)
Titre : The lambda method for integer ambiguity estimation : implementation aspects Type de document : Monographie Auteurs : P.J. de Jonge, Auteur ; Christian Tiberius, Auteur Editeur : Delft [Pays-Bas] : Delft University of Technology Année de publication : 1993 Collection : LGR-SERIES num. 12 Importance : 49 p. Format : 21 x 30 cm Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Statistiques
[Termes IGN] ambiguïté entière
[Termes IGN] compensation Lambda
[Termes IGN] décorrélation
[Termes IGN] méthode des moindres carrés
[Termes IGN] résolution d'ambiguïté
[Termes IGN] signal GPSRésumé : (Auteur) High precision relative GPS positioning is based on the very precise carrier phase measurements. In order to achieve high precision results within a short observation time span, the integer nature of the ambiguities has to be exploited. In this report the full procedure for parameter estimation based on the model of double difference GPS observations is reviewed, but the emphasis will be on the integer estirnation of the GPS double difference ambiguities. The LAMBDA method will be used for the integer estimation. LAMBDA stands for Least-squares AMBiguity Decorrelation Adjustment. By means of the Z-transformation, the ambiguities are decorrelated prior to the integer estimation. The integer minimization problem is then attacked by a discrete search over an ellipsoidal region, the ambiguity search ellipsoid. The shape and orientation of the ellipsoid are governed by the variance covariance matrix of the ambiguities. The decorrelation realizes an ellipsoid that is very much sphere-like. It can be searched through very efficiently. The size of the ellipsoid can be controlled prior to the search using the volume function. The volume gives an indication of the number of candidates contained in the ellipsoid. A request for only a few candidates can be made, and this enables a straightforward implementation of the search. A limited number of candidates will be output of which one is the integer least-squares estimate for the vector of ambiguities. The LAMBDA method provides, based on the float ambiguities and their variance covariance matrix, the integer least-squares estimate for the ambiguities. Therewith, the fixed solution can be computed. By the decorrelation, the integer estimation can be carried out very fast and efficiently. The total procedure typically takes 30 ms or less on a 486-66 MHz PC for a baseline with 12 ambiguities. The method has been introduced in [1]. Preliminary fast positioning results using the LAMBDA method are given in [8], [9] and [10]. In this report, the implementation aspects of the method are discussed. A detailed description of the method is given, as well as the algorithms in the stylized Matlab notation of [7]. Numéro de notice : 18213 Affiliation des auteurs : non IGN Thématique : MATHEMATIQUE Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=55353 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 18213-01 23.60 Livre Centre de documentation Mathématiques Disponible PermalinkZur Datumsfestlegung und Short-Arc Bahnverbesserung bei der Auswertung von GPS-Beobachtungen / Detlef Angermann (1991)PermalinkContributions to GPS studies / Chris Rizos (1990)PermalinkPseudo-kinematic GPS results using the ambiguity function method / B.W. Remondi (1990)PermalinkCours de trigonométrie / P. Chenevier (1934)Permalink