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Processing of GNSS constellations and ground station networks using the raw observation approach / Sebastian Strasser in Journal of geodesy, vol 93 n°7 (July 2019)  

Public [article]  inJournal of geodesy > vol 93 n°7 (July 2019) . - pp 1045 - 1057 Titre : Processing of GNSS constellations and ground station networks using the raw observation approach Type de document : Article/Communication Auteurs : Sebastian Strasser, Auteur ; Torsten Mayer-Gürr, Auteur ; Norbert Zehentner, Auteur Année de publication : 2019 Article en page(s) : pp 1045 - 1057 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes descripteurs IGN] analyse diachronique [Termes descripteurs IGN] antenne GNSS [Termes descripteurs IGN] constellation GNSS [Termes descripteurs IGN] données GPS [Termes descripteurs IGN] erreur systématique [Termes descripteurs IGN] étalonnage d'instrument [Termes descripteurs IGN] Global Orbitography Navigation Satellite System [Termes descripteurs IGN] horloge du satellite [Termes descripteurs IGN] orbitographie [Termes descripteurs IGN] position [Termes descripteurs IGN] repère de référence [Termes descripteurs IGN] retard ionosphèrique [Termes descripteurs IGN] station GNSS [Termes descripteurs IGN] station GPS Résumé : (auteur) This article describes the raw observation approach as implemented at Graz University of Technology to determine GNSS products like satellite orbits, clocks, and station positions. To assess the performance of the approach, 15 years (2003–2017) of observations from a network of 245 globally distributed IGS stations to the GPS constellation were processed on a daily basis using the IGS14 reference frame and antenna calibrations. The resulting products are evaluated against those determined by IGS analysis centers. Orbit fit quality relative to the IGS combination is comparable to the best-fitting solutions used for evaluation. Starting from early 2017, when the IGS switched to IGS14, the determined orbits fit better to the IGS combination than any other considered solution. Midnight discontinuities show good internal orbit consistency and no noticeable satellite block-dependency. Satellite clocks are comparable to the considered IGS analysis center solutions. Station positions differ from the IGS combination on a similar level to the solutions they were evaluated against. The temporal repeatability of station positions is slightly better than that of the IGS combination. The quality of resulting GNSS products confirms that the raw observation approach is well suited for the task of determining satellite orbits, clocks, and station positions. It provides an alternative to well-established approaches used by IGS analysis centers and simplifies the introduction of additional observables from new and modernized GNSS. Numéro de notice : A2019-358 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-018-1223-2 date de publication en ligne : 13/12/2018 En ligne : https://doi.org/10.1007/s00190-018-1223-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93426 [article]

Impact of GPS antenna phase center models on zenith wet delay and tropospheric gradients / Yohannes Getachew Ejigu in GPS solutions, vol 23 n° 1 (January 2019)  

Public [article]  inGPS solutions > vol 23 n° 1 (January 2019) Titre : Impact of GPS antenna phase center models on zenith wet delay and tropospheric gradients Type de document : Article/Communication Auteurs : Yohannes Getachew Ejigu, Auteur ; Addisu Hunegnaw, Auteur ; Kibrom Ebuy Abraha, Auteur ; et al., Auteur Année de publication : 2019 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes descripteurs IGN] antenne GPS [Termes descripteurs IGN] centre de phase [Termes descripteurs IGN] données GPS [Termes descripteurs IGN] gradient de troposphère [Termes descripteurs IGN] retard troposphérique zénithal [Termes descripteurs IGN] teneur intégré en vapeur d'eau [Vedettes matières IGN] Traitement de données GNSS Résumé : (Auteur) Today Global Navigation Satellite Systems (GNSS) tropospheric products, such as zenith total delays (ZTD) and zenith wet delays (ZWD), are widely used as complementary data sets in numerical weather prediction models. In particular, the wet delays are treated as unknown parameters in GNSS processing and are estimated with other parameters such as station coordinates. In this study, we investigate the effects of Phase Center Correction (PCC) models on ZWD, integrated water vapor (IWV) and horizontal gradients derived from Global Positioning System (GPS) observations. Two solutions were generated using the GAMIT software over the European Reference Frame (EUREF) Permanent GNSS Network (EPN). The first (reference) solution was derived by applying the International GNSS Service (IGS) type-mean PCC models, while for the second solution PCC models from individual calibrations were used. The solutions were generated identically, except for the PCC model differences. The tropospheric products from the two solutions were then compared, with the assumption that common signals would be differenced out. The comparison of the two solutions clearly shows a bias in all tropospheric products, which can be attributed to PCC model deficiencies. Overall, mean biases of 1.8, 0.3, 0.14 and 0.19 mm are evident in ZWD, IWV, North–South and East–West gradients, respectively. Moreover, the differences between the two solutions show seasonal variations. For all antenna types, the ZWD and IWV differences are dominated by white plus power-law noise, with the latter characterizing the low-frequency spectrum. On the other hand, the horizontal gradients exhibit a white plus first-order autoregressive noise characteristic with less than 1% white noise. The individual PCC model provides a better fit to an external independent model in terms of gradient estimates and also provides up to 3% more carrier phase integer ambiguity resolution. Numéro de notice : A2019-056 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-018-0796-9 date de publication en ligne : 25/10/2018 En ligne : https://doi.org/10.1007/s10291-018-0796-9 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92085 [article]

Validating and comparing GNSS antenna calibrations / Ulla Kallio in Journal of geodesy, vol 93 n° 1 (January 2019)  

Public [article]  inJournal of geodesy > vol 93 n° 1 (January 2019) . - pp 1 - 18 Titre : Validating and comparing GNSS antenna calibrations Type de document : Article/Communication Auteurs : Ulla Kallio, Auteur ; Hannu Koivula, Auteur ; Sonja Lahtinen, Auteur ; Ville Nikkonen, Auteur ; Markku Poutanen, Auteur Année de publication : 2019 Article en page(s) : pp 1 - 18 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes descripteurs IGN] antenne GNSS [Termes descripteurs IGN] centre de phase [Termes descripteurs IGN] erreur systématique [Termes descripteurs IGN] étalonnage d'instrument [Termes descripteurs IGN] matrice de covariance [Termes descripteurs IGN] Metsähovi [Termes descripteurs IGN] modèle mathématique [Termes descripteurs IGN] positionnement cinématique [Termes descripteurs IGN] précision millimétrique [Termes descripteurs IGN] résidu [Termes descripteurs IGN] test de performance Résumé : (auteur) GNSS antennas have no fixed electrical reference point. The variation of the phase centre is modelled and tabulated in antenna calibration tables, which include the offset vector (PCO) and phase centre variation (PCV) for each frequency according to the elevations and azimuths of the incoming signal. Used together, PCV and PCO reduce the phase observations to the antenna reference point. The remaining biases, called the residual offsets, can be revealed by circulating and rotating the antennas on pillars. The residual offsets are estimated as additional parameters when combining the daily GNSS network solutions with full covariance matrix. We present a procedure for validating the antenna calibration tables. The dedicated test field, called Revolver, was constructed at Metsähovi. We used the procedure to validate the calibration tables of 17 antennas. Tables from the IGS and three different calibration institutions were used. The tests show that we were able to separate the residual offsets at the millimetre level. We also investigated the influence of the calibration tables from the different institutions on site coordinates by performing kinematic double-difference baseline processing of the data from one site with different antenna tables. We found small but significant differences between the tables. Numéro de notice : A2019-031 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-018-1134-2 date de publication en ligne : 22/03/2019 En ligne : https://doi.org/10.1007/s00190-018-1134-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91968 [article]

Periodic signals in a pseudo-kinematic GPS coordinate time series depending on the antenna phase centre model – TRM55971.00 TZGD antenna case study / Karol Dawidowicz in Survey review, vol 49 n° 355 (October 2017)  

Public [article]  inSurvey review > vol 49 n° 355 (October 2017) . - pp 268 - 276 Titre : Periodic signals in a pseudo-kinematic GPS coordinate time series depending on the antenna phase centre model – TRM55971.00 TZGD antenna case study Type de document : Article/Communication Auteurs : Karol Dawidowicz, Auteur Année de publication : 2017 Article en page(s) : pp 268 - 276 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes descripteurs IGN] antenne GNSS [Termes descripteurs IGN] centre de phase [Termes descripteurs IGN] étalonnage des données [Termes descripteurs IGN] GPS en mode pseudo-cinématique [Termes descripteurs IGN] Pologne [Termes descripteurs IGN] série temporelle [Termes descripteurs IGN] station permanente [Vedettes matières IGN] Traitement de données GNSS Résumé : (Auteur) This study investigates the differences between position estimates obtained using individual and type-mean (igs08.atx) antenna calibration models in GPS pseudo-kinematic processing. We used 15-min observation windows to study the short-period oscillations. Continuous GPS observations from eight selected Polish EUREF Permanent Network stations with the same TRM55971.00 TZGD antenna were used. The results showed that the differences in the calibration models, directly propagate into the position domain, affecting sub-daily results and influencing periodic variations. The sub-daily variations have periods close to half a sidereal day with amplitudes of up to 10 mm in position components. It could also be demonstrated that the mean position offsets, resulting from the use of individual calibrations instead of type-mean igs08.atx calibrations, can reach up to 5 mm in the up component, while the offsets in the horizontal components generally remain below 1 mm. Numéro de notice : A2017-550 Thématique : POSITIONNEMENT Nature : Article DOI : 10.1080/00396265.2016.1166688 En ligne : https://doi.org/10.1080/00396265.2016.1166688 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86606 [article]

Multipath detection based on single orthogonal dual linear polarized GNSS antenna / Ke Zhang in GPS solutions, vol 21 n° 3 (July 2017)  

Public [article]  inGPS solutions > vol 21 n° 3 (July 2017) . - pp 1203–1211 Titre : Multipath detection based on single orthogonal dual linear polarized GNSS antenna Type de document : Article/Communication Auteurs : Ke Zhang, Auteur ; Baiyu Li, Auteur ; Xiangwei Zhu, Auteur ; et al., Auteur Année de publication : 2017 Article en page(s) : pp 1203–1211 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes descripteurs IGN] antenne GNSS [Termes descripteurs IGN] coordonnées géodésiques [Termes descripteurs IGN] ligne de visée [Termes descripteurs IGN] phase GNSS [Termes descripteurs IGN] trajet multiple [Vedettes matières IGN] Traitement de données GNSS Résumé : (auteur) Based on the polarization difference between the multipath and the line-of-sight (LOS) signal, a method for multipath detection using a single antenna is proposed. The antenna has two channels to receive two orthogonal linear polarized components of the multipath and LOS signal, respectively. A hypothetical model of the antenna is employed such that the antenna patterns of the channels are assumed identical regarding amplitude and phase and are independent of azimuth. The antenna gain in the direction below the local horizon is assumed to be larger than in the direction toward LOS signals. Parallel cross-cancellation is used to remove the LOS signal from the received signals based on the magnitude and phase difference between the two orthogonal components. Then the residual signals are processed by a conventional digital processor of global navigation satellite system. The multipath can be detected by parallel cross-cancellation in the receiver in real time. The proposed method makes use of the polarization and spatial information of the multipath and LOS signal, and can detect short-delay multipath. Numéro de notice : A2017-445 Thématique : POSITIONNEMENT Nature : Article En ligne : https://doi.org/10.1007/s10291-017-0603-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86366 [article]

GNSS antenna caused near-field interference effect in Precise Point Positioning results / Karol Dawidowicz in Artificial satellites, vol 52 n° 2 (June 2017)  

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GPS code phase variations (CPV) for GNSS receiver antennas and their effect on geodetic parameters and ambiguity resolution / Tobias Kersten in Journal of geodesy, vol 91 n° 6 (June 2017)  

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Fast ambiguity resolution for long-range reference station networks with ionospheric model constraint method / Ming Zhang in GPS solutions, vol 21 n° 2 (April 2017)  

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Springer handbook of Global Navigation Satellite Systems / Peter J.G. Teunissen (2017)

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Bundle adjustment of spherical images acquired with a portable panoramic image mapping system (PPIMS) / Yi-Hsing Tseng in Photogrammetric Engineering & Remote Sensing, PERS, vol 82 n° 12 (December 2016)  

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A remark on the GNSS single difference model with common clock scheme for attitude determination / Wantong Chen in Journal of applied geodesy, vol 10 n° 3 (September 2016)  

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Estimation of satellite antenna phase center offsets for Galileo / Peter Steigenberger in Journal of geodesy, vol 90 n° 8 (August 2016)  

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Ground-based phase wind-up and its application in yaw angle determination / M. Cai in Journal of geodesy, vol 90 n° 8 (August 2016)  

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The development and performance of the VeraPhase antenna / Julien Hautcoeur in GPS world, vol 27 n° 7 (July 2016)

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Inter-signal correction sensitivity analysis : aperture-dependent delays induced by antenna anisotropy in modernized GPS dual-frequency navigation / Gary Okerson in Inside GNSS, vol 11 n° 3 (May - June 2016)  

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