Descripteur
Documents disponibles dans cette catégorie (18)
Ajouter le résultat dans votre panier
Visionner les documents numériques
Affiner la recherche Interroger des sources externes
Etendre la recherche sur niveau(x) vers le bas
On the estimability of parameters in undifferenced, uncombined GNSS network and PPP-RTK user models by means of S-system theory / Dennis Odijk in Journal of geodesy, vol 90 n° 1 (January 2016)
[article]
Titre : On the estimability of parameters in undifferenced, uncombined GNSS network and PPP-RTK user models by means of S-system theory Type de document : Article/Communication Auteurs : Dennis Odijk, Auteur ; Baocheng Zhang, Auteur ; Amir Khodabandeh, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 15 - 44 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] constellation GNSS
[Termes IGN] positionnement cinématique en temps réel
[Termes IGN] positionnement ponctuel précis
[Termes IGN] temps réel
[Termes IGN] utilisateurRésumé : (auteur) The concept of integer ambiguity resolution-enabled Precise Point Positioning (PPP-RTK) relies on appropriate network information for the parameters that are common between the single-receiver user that applies and the network that provides this information. Most of the current methods for PPP-RTK are based on forming the ionosphere-free combination using dual-frequency Global Navigation Satellite System (GNSS) observations. These methods are therefore restrictive in the light of the development of new multi-frequency GNSS constellations, as well as from the point of view that the PPP-RTK user requires ionospheric corrections to obtain integer ambiguity resolution results based on short observation time spans. The method for PPP-RTK that is presented in this article does not have above limitations as it is based on the undifferenced, uncombined GNSS observation equations, thereby keeping all parameters in the model. Working with the undifferenced observation equations implies that the models are rank-deficient; not all parameters are unbiasedly estimable, but only combinations of them. By application of S-system theory the model is made of full rank by constraining a minimum set of parameters, or S-basis. The choice of this S-basis determines the estimability and the interpretation of the parameters that are transmitted to the PPP-RTK users. As this choice is not unique, one has to be very careful when comparing network solutions in different S-systems; in that case the S-transformation, which is provided by the S-system method, should be used to make the comparison. Knowing the estimability and interpretation of the parameters estimated by the network is shown to be crucial for a correct interpretation of the estimable PPP-RTK user parameters, among others the essential ambiguity parameters, which have the integer property which is clearly following from the interpretation of satellite phase biases from the network. The flexibility of the S-system method is furthermore demonstrated by the fact that all models in this article are derived in multi-epoch mode, allowing to incorporate dynamic model constraints on all or subsets of parameters. Numéro de notice : A2016-022 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-015-0854-9 Date de publication en ligne : 05/11/2015 En ligne : https://doi.org/10.1007/s00190-015-0854-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79465
in Journal of geodesy > vol 90 n° 1 (January 2016) . - pp 15 - 44[article]Visibility and geometry of global satellite navigation systems constellations / Jacek Januszewski in Artificial satellites, vol 50 n° 4 (December 2015)
[article]
Titre : Visibility and geometry of global satellite navigation systems constellations Type de document : Article/Communication Auteurs : Jacek Januszewski, Auteur Année de publication : 2015 Article en page(s) : pp 169 - 180 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] affaiblissement géométrique de la précision
[Termes IGN] constellation BeiDou
[Termes IGN] constellation Galileo
[Termes IGN] constellation GLONASS
[Termes IGN] constellation GNSS
[Termes IGN] constellation GPS
[Termes IGN] visibilitéRésumé : (auteur) Nowadays (November 2015) there are two global fully operational satellite navigation systems, American GPS and Russian GLONASS. Two next are under construction, Galileo in Europe and BeiDou in China. As the error of observer’s position obtained from these systems depends on geometry factor DOP (Dilution Of Precision) among other things the knowledge of the number of satellites visible by this observer above given masking elevation angle Hmin and the distributions of DOP coefficient values, GDOP in particular, is very important. The lowest and the greatest number of satellites visible in open area by the observer at different latitudes for different Hmin, the percentage of satellites visible above angle H (9 intervals, each 10O wide), distributions (in per cent) of satellites azimuths (8 intervals, each 45O wide) and GDOP coefficient values (8 intervals) for Hmin = 5O for all these four systems at different observer’s latitudes (9 intervals, each wide 10O wide) are presented in the paper. Additionally the lowest elevation for which the number of satellites visible at different latitudes by the observer in open area above this angle is equal 4 or 3 and the distributions (in per cent) of GDOP coefficient values for different Hmin at observer’s latitudes 50-60O for the same four systems are showed. All calculations were made for constellation of GPS 27 satellites, GLONASS 24, Galileo 30 and BeiDou 27 MEO satellites. Numéro de notice : A2015--041 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/arsa-2015-0014 En ligne : http://dx.doi.org/10.1515/arsa-2015-0014 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81760
in Artificial satellites > vol 50 n° 4 (December 2015) . - pp 169 - 180[article]Estimation of multi-constellation GNSS observation stochastic properties using single receiver single satellite data validation method / Ahmed El-Mowafy in Survey review, vol 47 n° 341 (March 2015)
[article]
Titre : Estimation of multi-constellation GNSS observation stochastic properties using single receiver single satellite data validation method Type de document : Article/Communication Auteurs : Ahmed El-Mowafy, Auteur Année de publication : 2015 Article en page(s) : pp 99 - 108 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] constellation GNSS
[Termes IGN] positionnement cinématique
[Termes IGN] positionnement par Galileo
[Termes IGN] positionnement par GLONASS
[Termes IGN] positionnement par GPS
[Termes IGN] positionnement statique
[Termes IGN] récepteur
[Termes IGN] validation des données
[Vedettes matières IGN] Traitement de données GNSSRésumé : (auteur) The single receiver single satellite validation method is a technique that screens data from each satellite independently to detect and identify faulty observations. A new method for estimation of the stochastic properties of multi-constellation GNSS observation is presented utilising parameters of this validation method. Agreement of the characteristics of the validation statistics with theory is used as the criterion to select the best precision of the observations, spectral density and correlation time of the unknowns. A curve fitting approach in an iterative scheme is employed. The method is applicable to any GNSS with any arbitrary number of frequencies. Demonstration of the method results and performance is given using multiple-frequency data from GPS, GLONASS and Galileo in static and kinematic modes. Numéro de notice : A2015-957 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1179/1752270614Y.0000000100 En ligne : https://doi.org/10.1179/1752270614Y.0000000100 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79942
in Survey review > vol 47 n° 341 (March 2015) . - pp 99 - 108[article]Positioning configurations with the lowest GDOP and their classification / Shuqiang Xue in Journal of geodesy, vol 89 n° 1 (January 2015)
[article]
Titre : Positioning configurations with the lowest GDOP and their classification Type de document : Article/Communication Auteurs : Shuqiang Xue, Auteur ; Yuanxi Yang, Auteur Année de publication : 2015 Article en page(s) : pp 49 - 71 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] affaiblissement géométrique de la précision
[Termes IGN] constellation GNSS
[Termes IGN] équation linéaire
[Termes IGN] erreur systématique
[Termes IGN] optimisation (mathématiques)
[Termes IGN] orbitographie
[Termes IGN] polyèdre
[Termes IGN] pseudoliteRésumé : (auteur) The positioning configuration optimization is a basic problem in surveying, and the geometric dilution of precision (GDOP) is a key index to handle this problem. Simplex graphs as regular polygons and regular polyhedrons are the well-known configurations with the lowest GDOP. However, it has been proved that there are at most five kinds of regular polyhedrons. We analytically solve the GDOP minimization problem with arbitrary observational freedom to extend the current knowledge. The configuration optimization framework established is composed of the algebraic and geometric operators (including combination, reflection, collinear mapping, projection and three kinds of equivalence relations), basic properties to GDOP minimization (including continuity, combination invariant, reflection invariant, rotation invariant and collinear invariant) and the lowest GDOP configurations (including cones, regular polygons, regular polyhedrons, Descartes configuration, helical configuration and generalized Walker configuration, and their reflections and combinations). GDOP minimization criterion and D-maximization criterion both reduce to the same criterion matrices that the optimization becomes the problem for solving an underdetermined quadratic equation system. Making use of the concepts for solving underdetermined linear equation system, the concepts of base configuration (single classification) and general configuration (combined classification) are applied to the GDOP minimization to analytically solve the quadratic equation system. Firstly, the problems are divided into two subproblems by two kinds of GDOP to reveal the impact of the clock-offset on the configuration optimization, and it shows that the symmetry and uniformity play a key role in identifying the systematic errors. Then, the solution of the GDOP minimization is classified by the number of symmetry axes, that the base configurations with at least one symmetry axis and the general configurations without symmetry axis are categorized to be two large classifications. Complex configurations can be then generated by the combination and the reflection of those base configurations with simplex structure, and this indicates that completely solving the GDOP minimization needs to solve the simplex classifications primarily. Ultimately, constrained or unconstrained configuration optimization examples including GDOP distribution analysis, single-global satellite navigation system (GNSS) or multi-GNSS constellation design, configuration optimization of pseudolites and configuration design of buoys for underwater positioning are performed by employing the properties, lemmas, theorems and corollaries proposed. Numéro de notice : A2015-330 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-014-0760-6 Date de publication en ligne : 14/10/2014 En ligne : https://doi.org/10.1007/s00190-014-0760-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76655
in Journal of geodesy > vol 89 n° 1 (January 2015) . - pp 49 - 71[article]