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Separation of atmospheric, oceanic and hydrological polar motion excitation mechanisms based on a combination of geometric and gravimetric space observations / F. Göttl in Journal of geodesy, vol 89 n° 4 (April 2015)  

Public [article]  inJournal of geodesy > vol 89 n° 4 (April 2015) . - pp 377 - 390 Titre : Separation of atmospheric, oceanic and hydrological polar motion excitation mechanisms based on a combination of geometric and gravimetric space observations Type de document : Article/Communication Auteurs : F. Göttl, Auteur ; M. Schmidt, Auteur ; Florian Seitz, Auteur ; Mathis Blossfeld, Auteur Année de publication : 2015 Article en page(s) : pp 377 - 390 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] atmosphère terrestre [Termes IGN] champ de pesanteur terrestre [Termes IGN] géodésie physique [Termes IGN] masse d'eau [Termes IGN] mouvement du pôle [Termes IGN] océanographie spatiale [Termes IGN] réseau de surveillance géophysique [Termes IGN] rotation de la Terre Résumé : (auteur) The goal of our study is to determine accurate time series of geophysical Earth rotation excitations to learn more about global dynamic processes in the Earth system. For this purpose, we developed an adjustment model which allows to combine precise observations from space geodetic observation systems, such as Satellite Laser Ranging (SLR), Global Navigation Satellite Systems, Very Long Baseline Interferometry, Doppler Orbit determination and Radiopositioning Integrated on Satellite, satellite altimetry and satellite gravimetry in order to separate geophysical excitation mechanisms of Earth rotation. Three polar motion time series are applied to derive the polar motion excitation functions (integral effect). Furthermore we use five time variable gravity field solutions from Gravity Recovery and Climate Experiment to determine not only the integral mass effect but also the oceanic and hydrological mass effects by applying suitable filter techniques and a land–ocean mask. For comparison the integral mass effect is also derived from degree 2 potential coefficients that are estimated from SLR observations. The oceanic mass effect is also determined from sea level anomalies observed by satellite altimetry by reducing the steric sea level anomalies derived from temperature and salinity fields of the oceans. Due to the combination of all geodetic estimated excitations the weaknesses of the individual processing strategies can be reduced and the technique-specific strengths can be accounted for. The formal errors of the adjusted geodetic solutions are smaller than the RMS differences of the geophysical model solutions. The improved excitation time series can be used to improve the geophysical modeling. Numéro de notice : A2015-343 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-014-0782-0 Date de publication en ligne : 18/12/2014 En ligne : https://doi.org/10.1007/s00190-014-0782-0 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76715 [article]

Using DORIS measurements for modeling the vertical total electron content of the Earth’s ionosphere / Denise Dettmering in Journal of geodesy, vol 88 n° 12 (December 2014)  

Public [article]  inJournal of geodesy > vol 88 n° 12 (December 2014) . - pp 1131 - 1143 Titre : Using DORIS measurements for modeling the vertical total electron content of the Earth’s ionosphere Type de document : Article/Communication Auteurs : Denise Dettmering, Auteur ; Marco Limberger, Auteur ; M. Schmidt, Auteur Année de publication : 2014 Article en page(s) : pp 1131 - 1143 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] données DORIS [Termes IGN] électron [Termes IGN] ionosphère [Termes IGN] teneur totale en électrons Résumé : (Auteur) The Doppler orbitography and radiopositioning integrated by satellite (DORIS) system was originally developed for precise orbit determination of low Earth orbiting (LEO) satellites. Beyond that, it is highly qualified for modeling the distribution of electrons within the Earth’s ionosphere. It measures with two frequencies in L-band with a relative frequency ratio close to 5. Since the terrestrial ground beacons are distributed quite homogeneously and several LEOs are equipped with modern receivers, a good applicability for global vertical total electron content (VTEC) modeling can be expected. This paper investigates the capability of DORIS dual-frequency phase observations for deriving VTEC and the contribution of these data to global VTEC modeling. The DORIS preprocessing is performed similar to commonly used global navigation satellite systems (GNSS) preprocessing. However, the absolute DORIS VTEC level is taken from global ionospheric maps (GIM) provided by the International GNSS Service (IGS) as the DORIS data contain no absolute information. DORIS-derived VTEC values show good consistency with IGS GIMs with a RMS between 2 and 3 total electron content units (TECU) depending on solar activity which can be reduced to less than 2 TECU when using only observations with elevation angles higher than 50∘ . The combination of DORIS VTEC with data from other space-geodetic measurement techniques improves the accuracy of global VTEC models significantly. If DORIS VTEC data is used to update IGS GIMs, an improvement of up to 12% can be achieved. The accuracy directly beneath the DORIS satellites’ ground-tracks ranges between 1.5 and 3.5 TECU assuming a precision of 2.5 TECU for altimeter-derived VTEC values which have been used for validation purposes. Numéro de notice : A2014-568 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-014-0748-2 Date de publication en ligne : 26/07/2014 En ligne : https://doi.org/10.1007/s00190-014-0748-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=74755 [article]

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Spatial knowledge acquisition with mobile maps, augmented reality and voice in the context of GPS-based pedestrian navigation: results from a field test / H. Huang in Cartography and Geographic Information Science, vol 39 n° 2 (April 2012)  

Public [article]  inCartography and Geographic Information Science > vol 39 n° 2 (April 2012) . - pp 107 - 116 Titre : Spatial knowledge acquisition with mobile maps, augmented reality and voice in the context of GPS-based pedestrian navigation: results from a field test Type de document : Article/Communication Auteurs : H. Huang, Auteur ; M. Schmidt, Auteur ; Georg Gartner, Auteur Année de publication : 2012 Article en page(s) : pp 107 - 116 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique web [Termes IGN] acquisition de connaissances [Termes IGN] analyse comparative [Termes IGN] appareil portable [Termes IGN] interface mobile [Termes IGN] interface web [Termes IGN] navigation pédestre [Termes IGN] positionnement par GPS [Termes IGN] réalité augmentée [Termes IGN] système de navigation [Termes IGN] utilisateur nomade [Termes IGN] voix Résumé : (Auteur) GPS-based pedestrian navigation systems have become increasingly popular. Different interface technologies can be used to communicate/convey route directions to pedestrians. This paper aims to empirically study the influence of different interface technologies on spatial knowledge acquisition in the context of GPS-based pedestrian navigation. A field experiment was implemented to address this concern. Firstly, the suitability of the evaluation methods in assessing spatial knowledge acquisition was analyzed empirically (focusing on the ability of differentiating “familiar“ and “unfamiliar“ participants). The suitable methods were then used to compare the influence of mobile maps, augmented reality, and voice on spatial learning. The field test showed that in terms of spatial knowledge acquisition, the three interface technologies led to comparable results, which were not significantly different from each other. The results bring some challenging issues for consideration when designing mobile pedestrian navigation systems. Numéro de notice : A2012-455 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1559/15230406392107 En ligne : https://doi.org/10.1559/15230406392107 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31901 [article]

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032-2012021	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Combination of different space-geodetic observations for regional ionosphere modeling / D. Dettmering in Journal of geodesy, vol 85 n° 12 (December 2011)  

Public [article]  inJournal of geodesy > vol 85 n° 12 (December 2011) . - pp 989 - 998 Titre : Combination of different space-geodetic observations for regional ionosphere modeling Type de document : Article/Communication Auteurs : D. Dettmering, Auteur ; M. Schmidt, Auteur ; Robert Heinkelmann, Auteur ; Manuela Seitz, Auteur Année de publication : 2011 Article en page(s) : pp 989 - 998 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] analyse combinatoire (maths) [Termes IGN] B-Spline [Termes IGN] correction ionosphérique [Termes IGN] ionosphère [Termes IGN] modèle ionosphérique [Termes IGN] teneur totale en électrons Résumé : (Auteur) Most of the space-geodetic observation techniques can be used for modeling the distribution of free electrons in the Earth’s ionosphere. By combining different techniques one can take advantage of their different spatial and temporal distributions as well as their different observation characteristics and sensitivities concerning ionospheric parameter estimation. The present publication introduces a procedure for multi-dimensional ionospheric modeling. The model consists of a given reference part and an unknown correction part expanded in terms of B-spline functions. This approach is used to compute regional models of Vertical Total Electron Content (VTEC) based on the International Reference Ionosphere (IRI 2007) and GPS observations from terrestrial Global Navigation Satellite System (GNSS) reference stations, radio occultation data from Low Earth Orbiters (LEOs), dual-frequency radar altimetry measurements, and data obtained by Very Long Baseline Interferometry (VLBI). The approach overcomes deficiencies in the climatological IRI model and reaches the same level of accuracy than GNSS-based VTEC maps from IGS. In areas without GNSS observations (e.g., over the oceans) radio occultations and altimetry provide valuable measurements and further improve the VTEC maps. Moreover, the approach supplies information on the offsets between different observation techniques as well as on their different sensitivity for ionosphere modeling. Altogether, the present procedure helps to derive improved ionospheric corrections (e.g., for one-frequency radar altimeters) and at the same time it improves our knowledge on the Earth’s ionosphere. Numéro de notice : A2011-504 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-010-0423-1 Date de publication en ligne : 10/11/2011 En ligne : https://doi.org/10.1007/s00190-010-0423-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31398 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
266-2011121	RAB	Revue	Centre de documentation	En réserve L003	Disponible

vol 85 n° 12 - December 2011 - Special issue : Ionosphere (Bulletin de Journal of geodesy) / M. Schmidt  

Public [n° ou bulletin]  est un bulletin de Journal of geodesy (1996 -)   Titre : vol 85 n° 12 - December 2011 - Special issue : Ionosphere Type de document : Périodique Auteurs : M. Schmidt, Éditeur scientifique ; International association of geodesy, Auteur Année de publication : 2011 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] International Reference Ionosphere [Termes IGN] ionosphère [Termes IGN] modèle ionosphérique Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Numéro de périodique En ligne : http://link.springer.com/journal/190/85/12/page/1 Format de la ressource électronique : URL sommaire Permalink : https://documentation.ensg.eu/index.php?lvl=bulletin_display&id=21768 [n° ou bulletin]

Contient

• The ionosphere : effects, GPS modeling and the benefits for space geodetic techniques / Manuel Hernández-Pajares in Journal of geodesy, vol 85 n° 12 (December 2011)  
• The international reference ionosphere today and in the future / Dieter Bilitza in Journal of geodesy, vol 85 n° 12 (December 2011)  
• Validation of international reference ionosphere models using in situ measurements from GRACE K-band ranging system and CHAMP planar Langmuir probe / C. Lee in Journal of geodesy, vol 85 n° 12 (December 2011)  
• Combination of different space-geodetic observations for regional ionosphere modeling / D. Dettmering in Journal of geodesy, vol 85 n° 12 (December 2011)  

Exemplaires(1)

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266-2011121	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Ein relativistisches Modell für PRARE-Beobachtungen / M. Schmidt (1990)

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