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Combined Architecture : Enhancing Multi-Dimensional Signal Quality in GNSS Receivers / Nunzia Giorgia Ferrara in Inside GNSS, vol 11 n° 2 (March - April 2016)
[article]
Titre : Combined Architecture : Enhancing Multi-Dimensional Signal Quality in GNSS Receivers Type de document : Article/Communication Auteurs : Nunzia Giorgia Ferrara, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 54 - 62 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] architecture logicielle
[Termes IGN] interférence
[Termes IGN] récepteur GNSS
[Termes IGN] signal GNSS
[Termes IGN] trajet multipleRésumé : (éditeur) Multipath, interference, and ionospheric effects represent some of the leading sources of error affecting GNSS signals. This article proposes a combined architecture for future GNSS receivers that addresses all three. Numéro de notice : A2016-264 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80790
in Inside GNSS > vol 11 n° 2 (March - April 2016) . - pp 54 - 62[article]Documents numériques
en open access
Combined ArchitectureAdobe Acrobat PDF GNSS & the Law: GLONASS and PNT in Russia / Alexey Bolkunov in Inside GNSS, vol 11 n° 2 (March - April 2016)
[article]
Titre : GNSS & the Law: GLONASS and PNT in Russia Type de document : Article/Communication Auteurs : Alexey Bolkunov, Auteur ; Ingo Bauman, Auteur Année de publication : 2016 Article en page(s) : pp 48 - 53 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] droit
[Termes IGN] Global Orbitography Navigation Satellite System
[Termes IGN] positionnement par GLONASS
[Termes IGN] règleRésumé : (éditeur) The Russian Federation has a large body of laws, rules, and regulations dealing with positioning, navigation, and timing in general and GLONASS in particular. This column provides an overview of the associated Russian legal environment, authored by a leader of PNT regulatory framework development at the Roscosmos Central Scientific Research Institute of Machine Building. Numéro de notice : A2016-263 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80788
in Inside GNSS > vol 11 n° 2 (March - April 2016) . - pp 48 - 53[article]Documents numériques
en open access
GNSS & the Law : GLONASSAdobe Acrobat PDF MIDAS robust trend estimator for accurate GPS station velocities without step detection / Geoffrey Blewitt in Journal of geophysical research : Solid Earth, vol 121 n° 3 (March 2016)
[article]
Titre : MIDAS robust trend estimator for accurate GPS station velocities without step detection Type de document : Article/Communication Auteurs : Geoffrey Blewitt, Auteur ; Corné Kremer, Auteur ; William C. Hammond, Auteur ; Julien Gazeaux , Auteur Année de publication : 2016 Article en page(s) : pp 2054 - 2068 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] Amérique du nord
[Termes IGN] coordonnées GPS
[Termes IGN] estimateur
[Termes IGN] méthode robuste
[Termes IGN] série temporelle
[Termes IGN] station GPS
[Termes IGN] valeur aberrante
[Termes IGN] vitesseRésumé : (auteur) Automatic estimation of velocities from GPS coordinate time series is becoming required to cope with the exponentially increasing flood of available data, but problems detectable to the human eye are often overlooked. This motivates us to find an automatic and accurate estimator of trend that is resistant to common problems such as step discontinuities, outliers, seasonality, skewness, and heteroscedasticity. Developed here, Median Interannual Difference Adjusted for Skewness (MIDAS) is a variant of the Theil‐Sen median trend estimator, for which the ordinary version is the median of slopes vij = (xj–xi)/(tj–ti) computed between all data pairs i > j. For normally distributed data, Theil‐Sen and least squares trend estimates are statistically identical, but unlike least squares, Theil‐Sen is resistant to undetected data problems. To mitigate both seasonality and step discontinuities, MIDAS selects data pairs separated by 1 year. This condition is relaxed for time series with gaps so that all data are used. Slopes from data pairs spanning a step function produce one‐sided outliers that can bias the median. To reduce bias, MIDAS removes outliers and recomputes the median. MIDAS also computes a robust and realistic estimate of trend uncertainty. Statistical tests using GPS data in the rigid North American plate interior show ±0.23 mm/yr root‐mean‐square (RMS) accuracy in horizontal velocity. In blind tests using synthetic data, MIDAS velocities have an RMS accuracy of ±0.33 mm/yr horizontal, ±1.1 mm/yr up, with a 5th percentile range smaller than all 20 automatic estimators tested. Considering its general nature, MIDAS has the potential for broader application in the geosciences. Numéro de notice : A2016--176 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1002/2015JB012552 Date de publication en ligne : 12/02/2016 En ligne : https://doi.org/10.1002/2015JB012552 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91799
in Journal of geophysical research : Solid Earth > vol 121 n° 3 (March 2016) . - pp 2054 - 2068[article]Documents numériques
en open access
MIDAS robust trend estimator ... - pdf éditeurAdobe Acrobat PDF Ionospheric corrections for single-frequency tracking of GNSS satellites by VLBI based on co-located GNSS / Benjamin Männel in Journal of geodesy, vol 90 n° 2 (February 2016)
[article]
Titre : Ionospheric corrections for single-frequency tracking of GNSS satellites by VLBI based on co-located GNSS Type de document : Article/Communication Auteurs : Benjamin Männel, Auteur ; Markus Rothacher, Auteur Année de publication : 2016 Article en page(s) : pp 189-203 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] co-positionnement
[Termes IGN] correction ionosphérique
[Termes IGN] positionnement par GNSS
[Termes IGN] positionnement par ITGB
[Termes IGN] poursuite de satellite
[Termes IGN] propagation ionosphériqueRésumé : (auteur) Tracking L-band signals of GNSS satellites by radio telescopes became a new observation type in recent years and will be used to improve reference system realizations and links between Earth- and space-fixed frames. First successful test observations were done, with the drawback of being single-frequency only. In order to correct the ionospheric delay by using GNSS phase observations from co-located receivers, the L4R approach was developed. Based on residuals derived by a least-squares processing of the GNSS geometry-free linear combination corresponding corrections could be derived. As a first validation step L4R corrections were applied to GNSS L1 data analysis. Station coordinate repeatibilities at the 1-cm level were obtained for baselines of a few thousand kilometers. Comparing the derived delay corrections to VLBI ionospheric delays for quasars located in same directions, differences with a standard deviation of 2.2 TECU could be achieved. Numéro de notice : A2016-035 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-015-0865-6 Date de publication en ligne : 27/10/2015 En ligne : https://doi.org/10.1007/s00190-015-0865-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79512
in Journal of geodesy > vol 90 n° 2 (February 2016) . - pp 189-203[article]
Titre : Co-location of geodetic observation techniques in space Type de document : Thèse/HDR Auteurs : Benjamin Männel, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2016 Autre Editeur : Zurich : Eidgenossische Technische Hochschule ETH - Ecole Polytechnique Fédérale de Zurich EPFZ Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 97 Importance : 200 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-43-7 Note générale : bibliographie
A thesis submitted to attain the degree of Doctor of Sciences of ETH Zurich (Eidg. Technische Hochschule Zürich)Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] antenne GPS
[Termes IGN] Bernese
[Termes IGN] centre de phase
[Termes IGN] co-positionnement
[Termes IGN] données GRACE
[Termes IGN] géocentre
[Termes IGN] interférométrie à très grande base
[Termes IGN] International Terrestrial Reference System
[Termes IGN] orbite basse
[Termes IGN] orbitographie
[Termes IGN] positionnement par GPS
[Termes IGN] poursuite de satellite
[Termes IGN] propagation ionosphérique
[Termes IGN] repère de référence
[Termes IGN] système international de référence célesteIndex. décimale : 30.60 Géodésie spatiale Résumé : (auteur) This thesis describes the combination of geodetic observation techniques on-board satellites. This socalled co-location in space provides a considerable potential regarding the improvements needed to realize a long-term accurate and stable terrestrial reference frame. The space ties (i.e., the offset vectors between the on-board sensors) introduces new geometrical connections between sensors of dfferent space geodetic techniques. This space ties can be provided easily to each fundamental site via space geodetic observations. Consequently, co-location in space allows to assess technique-specific error sources as systematic effects can be addressed either to a certain station or to a certain technique. Moreover, the additional introduced orbit dynamics improve the estimation of several geodetic parameters. Within this thesis the following core topics concerning co-location in space are discussed: orbit determination, the combination of ground and space GNSS observations, and VLBI Earth-orbiting satellite tracking. Highly accurate orbit determination is the prerequisite for a suitable co-location in space. Based on the Earth observation satellite missions GRACE, GOCE, and OSTM/Jason-2 orbit determination and the impact of modeling non gravitational perturbations is studied. The overall reached orbit accuracies are at the level of a few centimeters. The combination of ground and space-geodetic GNSS observations is studied based on the GPS observations derived by 53 ground stations and the four LEOs (low Earth orbiter). Adding one LEO to the ground-only processing decreases the formal errors of weekly geocenter estimates by around 20% which is eight times more than expected due to the increased number of observations. This shows the considerable potential of the combination of ground and LEO data. Comparing the derived geocenter time series against results from satellite laser ranging (SLR) shows a good agreement for annual amplitudes, whereas the annual phases shows considerable discrepancies in the x- and the z-component. Geocenter coordinates derived from surface load density coeficients estimated in a long-term solution show a better agreement to SLR solutions but without a significant impact of additional LEOs. Using the gravitational constraint GPS satellite antenna phase center offsets were estimated based on ground and LEO observations. The results show a significant benefit for the horizontal offsets as the introduced LEOs help to dissolve limiting correlations. Concerning single-frequency VLBI satellite tracking the L4R method is introduced to derive ionosphere delay corrections based on co-located GNSS observations. A 1 cm daily station coordinate repeatability is achieved in a single-frequency GNSS processing while introducing the L4R corrections. Differences to ionospheric delays derived from VLBI observations show also a good agreement. As VLBI satellite tracking is currently in an experimental stage Monte-Carlo simulations were performed for eight different satellite orbit types. For a GNSS constellation tracking, station coordinate repeatabilities are at the level of 0.7 and 1.2 cm for a regional and a global network, respectively. Station coordinate repeatabilities of around 1 cm were derived for simulated VLBI observation to a fictitious LEO with an altitude of 2000 km. The station coordinates estimated from simulated observations to E-GRIP and E-GRASP/Eratosthenes show larger uncertainties. Based on the results suggestions for future action items regarding co-location in space were formulated. The most important recommendations are, that the combination of ground- and space GNSS observations provides a considerable benefit for the determination of several parameters and that ionosphere delay corrections should be derived from co-located GNSS observations. Note de contenu : 1- Motivation and Introduction
2- Geodetic Observation Techniques in a Nutshell
3- Reference Systems and the Combination and Co-location of Space Geodetic Techniques
4- Investigations on GPS-based Precise Orbit Determination for Low Earth Orbiters
5- Investigations on the Combined Processing of Ground- and Space-based GPS Observations
6- Investigations on VLBI Satellite Tracking
7- Conclusions and OutlookNuméro de notice : 21987 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Note de thèse : PhD : Sciences : ETH Zurich : 2016 DOI : 10.3929/ethz-a-010811791 En ligne : https://www.research-collection.ethz.ch/handle/20.500.11850/125751 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91982 Réservation
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