Centre de documentation
scientifique

Dépouillements

Calibration of the clock-phase biases of GNSS networks: the closure-ambiguity approach / A. Lannes in Journal of geodesy, vol 87 n° 8 (August 2013)  

Public [article]  inJournal of geodesy > vol 87 n° 8 (August 2013) . - pp 709 - 831 Titre : Calibration of the clock-phase biases of GNSS networks: the closure-ambiguity approach Type de document : Article/Communication Auteurs : A. Lannes, Auteur ; J.L. Prieur, Auteur Année de publication : 2013 Article en page(s) : pp 709 - 831 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] ambiguïté entière [Termes IGN] erreur systématique [Termes IGN] étalonnage d'instrument [Termes IGN] horloge [Termes IGN] phase GNSS [Termes IGN] positionnement cinématique en temps réel [Termes IGN] positionnement par GNSS [Termes IGN] positionnement ponctuel précis [Termes IGN] réseau géodésique permanent Résumé : (Auteur) In global navigation satellite systems (GNSS), the problem of retrieving clock-phase biases from network data has a basic rank defect. We analyse the different ways of removing this rank defect, and define a particular strategy for obtaining these phase biases in a standard form. The minimum-constrained problem to be solved in the least-squares (LS) sense depends on some integer vector which can be fixed in an arbitrary manner. We propose to solve the problem via an undifferenced approach based on the notion of closure ambiguity. We present a theoretical justification of this closure-ambiguity approach (CAA), and the main elements for a practical implementation. The links with other methods are also established. We analyse all those methods in a unified interpretative framework, and derive functional relations between the corresponding solutions and our CAA solution. This could be interesting for many GNSS applications like real-time kinematic PPP for instance. To compare the methods providing LS estimates of clock-phase biases, we define a particular solution playing the role of reference solution. For this solution, when a phase bias is estimated for the first time, its fractional part is confined to the one-cycle width interval centred on zero; the integer-ambiguity set is modified accordingly. Our theoretical study is illustrated with some simple and generic examples; it could have applications in data processing of most GNSS networks, and particularly global networks using GPS, Glonass, Galileo, or BeiDou/Compass satellites. Numéro de notice : A2013-480 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-013-0641-4 Date de publication en ligne : 18/06/2013 En ligne : https://doi.org/10.1007/s00190-013-0641-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32618 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
266-2013081	SL	Revue	Centre de documentation	Revues en salle	Disponible

Impact of loading displacements on SLR-derived parameters and on the consistency between GNSS and SLR results / Krzysztof Sosnica in Journal of geodesy, vol 87 n° 8 (August 2013)  

Public [article]  inJournal of geodesy > vol 87 n° 8 (August 2013) . - pp 751 - 769 Titre : Impact of loading displacements on SLR-derived parameters and on the consistency between GNSS and SLR results Type de document : Article/Communication Auteurs : Krzysztof Sosnica, Auteur ; Daniela Thaller, Auteur ; Rolf Dach, Auteur ; Adrian Jäggi, Auteur ; Gerhard Beutler, Auteur Année de publication : 2013 Article en page(s) : pp 751 - 769 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] cohérence des données [Termes IGN] effet de charge [Termes IGN] point de liaison (géodésie) [Termes IGN] positionnement par GNSS [Termes IGN] surcharge atmosphérique [Termes IGN] surcharge océanique [Termes IGN] télémétrie laser sur satellite Résumé : (Auteur) Displacements of the Earth’s surface caused by tidal and non-tidal loading forces are relevant in high-precision space geodesy. Some of the corrections are recommended by the international scientific community to be applied at the observation level, e.g., ocean tidal loading (OTL) and atmospheric tidal loading (ATL). Non-tidal displacement corrections are in general recommended not to be applied in the products of the International Earth Rotation and Reference Systems Service, in particular atmospheric non-tidal loading (ANTL), oceanic and hydrological non-tidal corrections. We assess and compare the impact of OTL, ATL and ANTL on SLR-derived parameters by reprocessing 12 years of SLR data considering and ignoring individual corrections. We show that loading displacements have an influence not only on station long-term stability, but also on geocenter coordinates, Earth Rotation Parameters, and satellite orbits. Applying the loading corrections reduces the amplitudes of annual signals in the time series of geocenter and station coordinates. The general improvement of the SLR station 3D coordinate repeatability when applying OTL, ATL and ANTL corrections are 19.5 %, 0.2 % and 3.3 % respectively, w.r.t. the solutions without loading corrections. ANTL corrections play a crucial role in the combination of optical (SLR) and microwave (GNSS, VLBI, DORIS) space geodetic observation techniques, because of the so-called Blue-Sky effect: SLR measurements can be carried out only under cloudless sky conditions—typically during high air pressure conditions, when the Earth’s crust is deformed, whereas microwave observations are weather-independent. Thus, applying the loading corrections at the observation level improves SLR-derived products as well as the consistency with microwave-based results. We assess the Blue-Sky effect on SLR stations and the consistency improvement between GNSS and SLR solutions when ANTL corrections are included. The omission of ANTL corrections may lead to inconsistencies between SLR and GNSS solutions of up to 2.5 mm for inland stations. As a result, the estimated GNSS–SLR coordinate differences correspond better to the local ties at the co-located stations when applying ANTL corrections. Numéro de notice : A2013-481 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-013-0644-1 Date de publication en ligne : 28/05/2013 En ligne : https://doi.org/10.1007/s00190-013-0644-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32619 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
266-2013081	SL	Revue	Centre de documentation	Revues en salle	Disponible

Canadian gravimetric geoid model 2010 / Jianliang Huang in Journal of geodesy, vol 87 n° 8 (August 2013)  

Public [article]  inJournal of geodesy > vol 87 n° 8 (August 2013) . - pp 771 - 790 Titre : Canadian gravimetric geoid model 2010 Type de document : Article/Communication Auteurs : Jianliang Huang, Auteur ; Marc Véronneau, Auteur Année de publication : 2013 Article en page(s) : pp 771 - 790 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] Canada [Termes IGN] géoïde gravimétrique [Termes IGN] levé gravimétrique [Termes IGN] modèle de géopotentiel local Résumé : (Auteur) A new gravimetric geoid model, Canadian Gravimetric Geoid 2010 (CGG2010), has been developed to upgrade the previous geoid model CGG2005. CGG2010 represents the separation between the reference ellipsoid of GRS80 and the Earth’s equipotential surface of W0=62,636,855.69 m2s-2 . The Stokes–Helmert method has been re-formulated for the determination of CGG2010 by a new Stokes kernel modification. It reduces the effect of the systematic error in the Canadian terrestrial gravity data on the geoid to the level below 2 cm from about 20 cm using other existing modification techniques, and renders a smooth spectral combination of the satellite and terrestrial gravity data. The long wavelength components of CGG2010 include the GOCE contribution contained in a combined GRACE and GOCE geopotential model: GOCO01S, which ranges from -20.1 to 16.7 cm with an RMS of 2.9 cm. Improvement has been also achieved through the refinement of geoid modelling procedure and the use of new data. (1) The downward continuation effect has been accounted accurately ranging from -22.1 to 16.5 cm with an RMS of 0.9 cm. (2) The geoid residual from the Stokes integral is reduced to 4 cm in RMS by the use of an ultra-high degree spherical harmonic representation of global elevation model for deriving the reference Helmert field in conjunction with a derived global geopotential model. (3) The Canadian gravimetric geoid model is published for the first time with associated error estimates. In addition, CGG2010 includes the new marine gravity data, ArcGP gravity grids, and the new Canadian Digital Elevation Data (CDED) 1:50K. CGG2010 is compared to GPS-levelling data in Canada. The standard deviations are estimated to vary from 2 to 10 cm with the largest error in the mountainous areas of western Canada. We demonstrate its improvement over the previous models CGG2005 and EGM2008. Numéro de notice : A2013-482 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-013-0645-0 Date de publication en ligne : 12/06/2013 En ligne : https://doi.org/10.1007/s00190-013-0645-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32620 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
266-2013081	SL	Revue	Centre de documentation	Revues en salle	Disponible

Automated and continual determination of radio telescope reference points with sub-mm accuracy: results from a campaign at the Onsala Space Observatory / Michael Lösler in Journal of geodesy, vol 87 n° 8 (August 2013)  

Public [article]  inJournal of geodesy > vol 87 n° 8 (August 2013) . - pp 791 - 804 Titre : Automated and continual determination of radio telescope reference points with sub-mm accuracy: results from a campaign at the Onsala Space Observatory Type de document : Article/Communication Auteurs : Michael Lösler, Auteur ; Rüdiger Haas, Auteur ; Cornelia Eschelbach, Auteur Année de publication : 2013 Article en page(s) : pp 791 - 804 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] Global Geodetic Observing System [Termes IGN] interférométrie à très grande base [Termes IGN] point d'appui [Termes IGN] précision submillimétrique [Termes IGN] radiotélescope Résumé : (Auteur) The Global Geodetic Observing System (GGOS) requires sub-mm accuracy, automated and continual determinations of the so-called local tie vectors at co-location stations. Co-location stations host instrumentation for several space geodetic techniques and the local tie surveys involve the relative geometry of the reference points of these instruments. Thus, these reference points need to be determined in a common coordinate system, which is a particular challenge for rotating equipment like radio telescopes for geodetic Very Long Baseline Interferometry. In this work we describe a concept to achieve automated and continual determinations of radio telescope reference points with sub-mm accuracy. We developed a monitoring system, including Java-based sensor communication for automated surveys, network adjustment and further data analysis. This monitoring system was tested during a monitoring campaign performed at the Onsala Space Observatory in the summer of 2012. The results obtained in this campaign show that it is possible to perform automated determination of a radio telescope reference point during normal operations of the telescope. Accuracies on the sub-mm level can be achieved, and continual determinations can be realized by repeated determinations and recursive estimation methods Numéro de notice : A2013-483 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-013-0647-y Date de publication en ligne : 12/06/2013 En ligne : https://doi.org/10.1007/s00190-013-0647-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32621 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
266-2013081	SL	Revue	Centre de documentation	Revues en salle	Disponible