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GNSS algebraic structures / A. Lannes in Journal of geodesy, vol 85 n° 5 (May 2011)  

Public [article]  inJournal of geodesy > vol 85 n° 5 (May 2011) . - pp 273 - 290 Titre : GNSS algebraic structures Type de document : Article/Communication Auteurs : A. Lannes, Auteur ; Peter J.G. Teunissen, Auteur Année de publication : 2011 Article en page(s) : pp 273 - 290 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] double différence [Termes IGN] erreur systématique [Termes IGN] étalonnage d'instrument [Termes IGN] mesurage de phase [Termes IGN] phase GNSS [Termes IGN] positionnement cinématique en temps réel [Termes IGN] positionnement par GNSS [Termes IGN] positionnement ponctuel précis Résumé : (Auteur) The first objective of this paper is to show that some basic concepts used in global navigation satellite systems (GNSS) are similar to those introduced in Fourier synthesis for handling some phase calibration problems. In experimental astronomy, the latter are at the heart of what is called phase closure imaging.' In both cases, the analysis of the related structures appeals to the algebraic graph theory and the algebraic number theory. For example, the estimable functions of carrier-phase ambiguities, which were introduced in GNSS to correct some rank defects of the undifferenced equations, prove to be closure-phase ambiguities:' the so-called closure-delay' (CD) ambiguities. The notion of closure delay thus generalizes that of double difference (DD). The other estimable functional variables involved in the phase and code undifferenced equations are the receiver and satellite pseudo-clock biases. A related application, which corresponds to the second objective of this paper, concerns the definition of the clock information to be broadcasted to the network users for their precise point positioning (PPP). It is shown that this positioning can be achieved by simply having access to the satellite pseudo-clock biases. For simplicity, the study is restricted to relatively small networks. Concerning the phase for example, these biases then include five components: a frequency-dependent satellite-clock error, a tropospheric satellite delay, an ionospheric satellite delay, an initial satellite phase, and an integer satellite ambiguity. The form of the PPP equations to be solved by the network user is then similar to that of the traditional PPP equations. As soon as the CD ambiguities are fixed and validated, an operation which can be performed in real time via appropriate decorrelation techniques, estimates of these float biases can be immediately obtained. No other ambiguity is to be fixed. The satellite pseudo-clock biases can thus be obtained in real time. This is not the case for the satellite-clock biases. The third objective of this paper is to make the link between the CD approach and the GNSS methods based on the notion of double difference. In particular, it is shown that the information provided by a maximum set of independent DDs may not reach that of a complete set of CDs. The corresponding defect is analyzed. One of the main results of the corresponding analysis concerns the DDCD relationship. In particular, it is shown that the DD ambiguities, once they have been fixed and validated, can be used as input data in the undifferenced CD equations.' The corresponding algebraic operations are described. The satellite pseudo-clock biases can therefore be also obtained via particular methods in which the notion of double differencing is involved. Numéro de notice : A2011-198 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-010-0435-x Date de publication en ligne : 05/01/2011 En ligne : https://doi.org/10.1007/s00190-010-0435-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30976 [article]

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266-2011051	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Combination of GNSS and SLR observations using satellite co-locations / Daniela Thaller in Journal of geodesy, vol 85 n° 5 (May 2011)  

Public [article]  inJournal of geodesy > vol 85 n° 5 (May 2011) . - pp 257 - 272 Titre : Combination of GNSS and SLR observations using satellite co-locations Type de document : Article/Communication Auteurs : Daniela Thaller, Auteur ; Rolf Dach, Auteur ; Manuela Seitz, Auteur ; et al., Auteur Année de publication : 2011 Article en page(s) : pp 257 - 272 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] co-positionnement [Termes IGN] données GNSS [Termes IGN] données TLS (télémétrie) [Termes IGN] erreur systématique [Termes IGN] système de référence mondial [Termes IGN] traitement combiné Résumé : (Auteur) Satellite Laser Ranging (SLR) observations to Global Navigation Satellite System (GNSS) satellites may be used for several purposes. On one hand, the range measurement may be used as an independent validation for satellite orbits derived solely from GNSS microwave observations. On the other hand, both observation types may be analyzed together to generate a combined orbit. The latter procedure implies that one common set of orbit parameters is estimated from GNSS and SLR data. We performed such a combined processing of GNSS and SLR using the data of the year 2008. During this period, two GPS and four GLONASS satellites could be used as satellite co-locations. We focus on the general procedure for this type of combined processing and the impact on the terrestrial reference frame (including scale and geocenter), the GNSS satellite antenna offsets (SAO) and the SLR range biases. We show that the combination using only satellite co-locations as connection between GNSS and SLR is possible and allows the estimation of SLR station coordinates at the level of 1–2 cm. The SLR observations to GNSS satellites provide the scale allowing the estimation of GNSS SAO without relying on the scale of any a priori terrestrial reference frame. We show that the necessity to estimate SLR range biases does not prohibit the estimation of GNSS SAO. A good distribution of SLR observations allows a common estimation of the two parameter types. The estimated corrections for the GNSS SAO are 119 mm and -13 mm on average for the GPS and GLONASS satellites, respectively. The resulting SLR range biases suggest that it might be sufficient to estimate one parameter per station representing a range bias common to all GNSS satellites. The estimated biases are in the range of a few centimeters up to 5 cm. Scale differences of 0.9 ppb are seen between GNSS and SLR. Numéro de notice : A2011-244 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-010-0435-x Date de publication en ligne : 02/04/2011 En ligne : https://doi.org/10.1007/s00190-010-0435-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31022 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
266-2011051	RAB	Revue	Centre de documentation	En réserve L003	Disponible