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Galileo and QZSS precise orbit and clock determination using new satellite metadata / Xingxing Li in Journal of geodesy, vol 93 n° 8 (August 2019)  

Public [article]  inJournal of geodesy > vol 93 n° 8 (August 2019) . - pp 1123 - 1136 Titre : Galileo and QZSS precise orbit and clock determination using new satellite metadata Type de document : Article/Communication Auteurs : Xingxing Li, Auteur ; Yongqiang Yuan, Auteur ; Jiande Huang, Auteur ; et al., Auteur Année de publication : 2019 Article en page(s) : pp 1123 - 1136 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes descripteurs IGN] Capacité opérationnelle totale [Termes descripteurs IGN] centre de phase [Termes descripteurs IGN] constellation Galileo [Termes descripteurs IGN] données satellitaires [Termes descripteurs IGN] GIOVE (satellite) [Termes descripteurs IGN] horloge du satellite [Termes descripteurs IGN] lacet [Termes descripteurs IGN] métadonnées [Termes descripteurs IGN] modèle d'orbite [Termes descripteurs IGN] orbite précise [Termes descripteurs IGN] orbitographie [Termes descripteurs IGN] Quasi-Zenith Satellite System [Termes descripteurs IGN] rayonnement solaire [Termes descripteurs IGN] variance d'Allan Résumé : (auteur) During 2016–2018, satellite metadata/information including antenna parameters, attitude laws and physical characteristics such as mass, dimensions and optical properties were released for Galileo and QZSS (except for the QZS-1 optical coefficients). These metadata are critical for improving the accuracy of precise orbit and clock determination. In this contribution, we evaluate the benefits of these new metadata to orbit and clock in three aspects: the phase center offsets and variations (PCO and PCV), the yaw-attitude model and solar radiation pressure (SRP) model. The updating of Galileo PCO and PCV corrections, from the values estimated by Deutsches Zentrum für Luft- und Raumfahrt and Deutsches GeoForschungsZentrum to the chamber calibrations disclosed by new metadata, has only a slight influence on Galileo orbits, with overlap differences within only 1 mm. By modeling the yaw attitude of Galileo satellites and QZS-2 spacecraft (SVN J002) according to new published attitude laws, the residuals of ionosphere-free carrier-phase combinations can be obviously decreased in yaw maneuver seasons. With the new attitude models, the 3D overlap RMS in eclipse seasons can be decreased from 12.3 cm, 14.7 cm, 16.8 cm and 34.7 cm to 11.7 cm, 13.4 cm, 15.8 cm and 32.9 cm for Galileo In-Orbit Validation (IOV), Full Operational Capability (FOC), FOC in elliptical orbits (FOCe) and QZS-2 satellites, respectively. By applying the a priori box-wing SRP model with new satellite dimensions and optical coefficients, the 3D overlap RMS are 5.3 cm, 6.2 cm, 5.3 cm and 16.6 cm for Galileo IOV, FOCe, FOC and QZS-2 satellites, with improvements of 11.0%, 14.7%, 14.0% and 13.8% when compared with the updated Extended CODE Orbit Model (ECOM2). The satellite laser ranging (SLR) validation reveals that the a priori box-wing model has smaller mean biases of − 0.4 cm, − 0.4 cm and 0.6 cm for Galileo FOCe, FOC and QZS-2 satellites, while a slightly larger mean bias of − 1.0 cm is observed for Galileo IOV satellites. Moreover, the SLR residual dependencies of Galileo IOV and FOC satellites on the elongation angle almost vanish when the a priori box-wing SRP model is applied. As for satellite clocks, a visible bump appears in the Modified Allan deviation at integration time of 20,000 s for Galileo Passive Hydrogen Maser with ECOM2, while it almost vanishes when the a priori box-wing SRP model and new metadata are applied. The standard deviations of clock overlap can also be significantly reduced by using new metadata. Numéro de notice : A2019-383 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-019-01230-4 date de publication en ligne : 02/02/2019 En ligne : https://doi.org/10.1007/s00190-019-01230-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93462 [article]

Improving multi-GNSS ultra-rapid orbit determination for real-time precise point positioning / Xingxing Li in Journal of geodesy, vol 93 n° 1 (January 2019)  

Public [article]  inJournal of geodesy > vol 93 n° 1 (January 2019) . - pp 45 - 64 Titre : Improving multi-GNSS ultra-rapid orbit determination for real-time precise point positioning Type de document : Article/Communication Auteurs : Xingxing Li, Auteur ; Xinghan Chen, Auteur ; Maorong Ge, Auteur ; Harald Schuh, Auteur Année de publication : 2019 Article en page(s) : pp 45 - 64 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes descripteurs IGN] délai d'obtention de la première position [Termes descripteurs IGN] orbite précise [Termes descripteurs IGN] orbitographie [Termes descripteurs IGN] positionnement par BeiDou [Termes descripteurs IGN] positionnement par Galileo [Termes descripteurs IGN] positionnement par GLONASS [Termes descripteurs IGN] positionnement par GNSS [Termes descripteurs IGN] positionnement ponctuel précis [Termes descripteurs IGN] Quasi-Zenith Satellite System [Termes descripteurs IGN] temps réel Résumé : (auteur) Currently, with the rapid development of multi-constellation Global Navigation Satellite Systems (GNSS), the real-time positioning and navigation are undergoing dramatic changes with potential for a better performance. To provide more precise and reliable ultra-rapid orbits is critical for multi-GNSS real-time positioning, especially for the three merging constellations Beidou, Galileo and QZSS which are still under construction. In this contribution, we present a five-system precise orbit determination (POD) strategy to fully exploit the GPS + GLONASS + BDS + Galileo + QZSS observations from CDDIS + IGN + BKG archives for the realization of hourly five-constellation ultra-rapid orbit update. After adopting the optimized 2-day POD solution (updated every hour), the predicted orbit accuracy can be obviously improved for all the five satellite systems in comparison to the conventional 1-day POD solution (updated every 3 h). The orbit accuracy for the BDS IGSO satellites can be improved by about 80, 45 and 50% in the radial, cross and along directions, respectively, while the corresponding accuracy improvement for the BDS MEO satellites reaches about 50, 20 and 50% in the three directions, respectively. Furthermore, the multi-GNSS real-time precise point positioning (PPP) ambiguity resolution has been performed by using the improved precise satellite orbits. Numerous results indicate that combined GPS + BDS + GLONASS + Galileo (GCRE) kinematic PPP ambiguity resolution (AR) solutions can achieve the shortest time to first fix (TTFF) and highest positioning accuracy in all coordinate components. With the addition of the BDS, GLONASS and Galileo observations to the GPS-only processing, the GCRE PPP AR solution achieves the shortest average TTFF of 11 min with 7∘ cutoff elevation, while the TTFF of GPS-only, GR, GE and GC PPP AR solution is 28, 15, 20 and 17 min, respectively. As the cutoff elevation increases, the reliability and accuracy of GPS-only PPP AR solutions decrease dramatically, but there is no evident decrease for the accuracy of GCRE fixed solutions which can still achieve an accuracy of a few centimeters in the east and north components. Numéro de notice : A2019-032 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-018-1138-y date de publication en ligne : 27/03/2018 En ligne : https://doi.org/10.1007/s00190-018-1138-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91969 [article]

An investigation into the performance of real-time GPS + GLONASS Precise Point Positioning (PPP) in New Zealand / Ken Harima in Journal of applied geodesy, vol 11 n° 3 (September 2017)  

Public [article]  inJournal of applied geodesy > vol 11 n° 3 (September 2017) . - pp 185 - 196 Titre : An investigation into the performance of real-time GPS + GLONASS Precise Point Positioning (PPP) in New Zealand Type de document : Article/Communication Auteurs : Ken Harima, Auteur ; Suelynn Choy, Auteur ; Chris Rizos, Auteur ; Satoshi Kogure, Auteur Année de publication : 2017 Article en page(s) : pp 185 - 196 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes descripteurs IGN] données GNSS [Termes descripteurs IGN] Nouvelle-Zélande [Termes descripteurs IGN] positionnement par GLONASS [Termes descripteurs IGN] positionnement par GPS [Termes descripteurs IGN] positionnement ponctuel précis [Termes descripteurs IGN] Quasi-Zenith Satellite System [Termes descripteurs IGN] système d'extension [Termes descripteurs IGN] temps réel Résumé : (Auteur) This paper presents an investigation into the performance of real-time Global Navigation Satellite Systems (GNSS) Precise Point Positioning (PPP) in New Zealand. The motivation of the research is to evaluate the feasibility of using PPP technique and a satellite based augmentation system such as the Japanese Quasi-Zenith Satellite System (QZSS) to deliver a real-time precise positioning solution in support of a nation-wide high accuracy GNSS positioning coverage in New Zealand. Two IGS real-time correction streams are evaluated alongside with the PPP correction messages transmitted by the QZSS satellite known as MDC1. MDC1 corrections stream is generated by Japan Aerospace Exploration Agency (JAXA) using the Multi-GNSS Advanced Demonstration tool for Orbit and Clock Analysis (MADOCA) software and are currently transmitted in test mode by the QZSS satellite. The IGS real-time streams are the CLK9B real-time corrections stream generated by the French Centre National D’études Spatiales (CNES) using the PPP-Wizard software, and the CLK81 real-time corrections stream produced by GMV using their MagicGNSS software. GNSS data is collected from six New Zealand CORS stations operated by Land Information New Zealand (LINZ) over a one-week period in 2015. GPS and GLONASS measurements are processed in a real-time PPP mode using the satellite orbit and clock corrections from the real-time streams. The results show that positioning accuracies of 6 cm in horizontal component and 15 cm in vertical component can be achieved in real-time PPP. The real-time GPS+GLONASS PPP solution required 30 minutes to converge to within 10 cm horizontal positioning accuracy. Numéro de notice : A2017-571 Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jag-2016-0035 En ligne : https://doi.org/10.1515/jag-2016-0035 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86691 [article]

Application of satellite navigation system for emergency warning and alerting / Suelynn Choy in Computers, Environment and Urban Systems, vol 58 (July 2016)  

Public [article]  inComputers, Environment and Urban Systems > vol 58 (July 2016) . - pp 12 - 18 Titre : Application of satellite navigation system for emergency warning and alerting Type de document : Article/Communication Auteurs : Suelynn Choy, Auteur ; John Handmer, Auteur ; Joshua Whittaker, Auteur ; Yuki Shinohara, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 12 - 18 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes descripteurs IGN] Australie [Termes descripteurs IGN] Japon [Termes descripteurs IGN] message d'alerte [Termes descripteurs IGN] Quasi-Zenith Satellite System [Termes descripteurs IGN] téléphonie mobile [Termes descripteurs IGN] urgence Résumé : (auteur) One of the key responsibilities of any government is to communicate and disseminate safety information and warnings to the general public in case of an emergency. Traditionally, warnings are issued by the government through a broadcast approach using communication channels such as TV and radio. However this monopolistic approach is now challenged by new technologies and media capable of providing individualised warnings to personal mobile devices. Location-based emergency services and mobile alerts are becoming increasingly prevalent in the provision of emergency warnings. These new modes of emergency services have been adopted by several countries worldwide including Australia. One example is the Australian National Emergency Alert (EA) which is a telephone-based service enhanced with location-based capabilities. This paper introduces the concept of applying global satellite navigation systems such as the Japanese satellite system in the domain of emergency warning and alerting. The Japanese satellite warning system can be tailored to transmit real-time location-based emergency warnings to people's mobile devices while not being constrained by the limitations of ground-based communication technologies. A key advantage of satellite based communication is its high resilience to communication network overload and failure of ground systems and network infrastructure during a disaster. This enables people to obtain necessary information anywhere (outdoor) and anytime during times of disaster. A satellite-based warning system could also be integrated with existing warning services and be used as a complementary technology. This paper examines opportunities and challenges for using satellite navigation systems to deliver warnings and safety messages during emergencies and disasters. Numéro de notice : A2016-403 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern En ligne : http://dx.doi.org/10.1016/j.compenvurbsys.2016.03.003 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81218 [article]

Wide-area ionospheric delay model for GNSS users in middle- and low-magnetic-latitude regions / An-Lin Tao in GPS solutions, vol 20 n° 1 (January 2016)  

Public [article]  inGPS solutions > vol 20 n° 1 (January 2016) . - pp 9 - 21 Titre : Wide-area ionospheric delay model for GNSS users in middle- and low-magnetic-latitude regions Type de document : Article/Communication Auteurs : An-Lin Tao, Auteur ; Shau-Shiun Jan, Auteur Année de publication : 2016 Article en page(s) : pp 9 - 21 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes descripteurs IGN] analyse comparative [Termes descripteurs IGN] Asie (géographie politique) [Termes descripteurs IGN] modèle ionosphérique [Termes descripteurs IGN] Quasi-Zenith Satellite System [Termes descripteurs IGN] retard ionosphèrique [Termes descripteurs IGN] station permanente [Vedettes matières IGN] Traitement de données GNSS Résumé : (Auteur) A useful ionospheric delay model to compensate for the effect of ionospheric error on GNSS service over continent-wide areas or oceans is the Satellite-Based Augmentation System’s wide-area thin-shell planar fit ionospheric grid model. In order to implement a proper wide-area ionospheric delay model in the Asia-Pacific region to reflect the variation introduced by local ionospheric activity, the present study develops a proper ionospheric delay model to correct ionospheric error in middle- and low-magnetic-latitude regions. Specifically, the proposed ionospheric delay model uses several dual-frequency GNSS reference stations distributed in Taiwan, South Korea, Japan, and China as grid points in place of the conventional grid points generated by ionospheric pierce points. The ionospheric delays observed at the reference stations are processed and provided to the user, who can then construct the ionospheric delay model using weighted least squares with the distances between the user and the stations as weights. This proposed ionospheric delay model lowers the computation load by eliminating the conversion of delays at the ionospheric pierce points to those at the grid points and provides good descriptions of dynamic variations due to the ionospheric activities. Also, a simplified model is developed to further reduce its computation load while providing almost the same service as that of the original proposed model. A selection mechanism between the original proposed model and its simplified version is developed as well. The details of the proposed ionospheric delay model are explained, and experiments conducted using data collected from the reference stations in the Asia-Pacific region are presented. The effectiveness of the proposed model is validated by comparison with the conventional wide-area thin-shell planar fit ionospheric grid model provided by the Japanese Multi-functional Satellite Augmentation System under both nominal and disturbed ionospheric conditions. Numéro de notice : A2016-601 Thématique : POSITIONNEMENT Nature : Article En ligne : http://dx.doi.org/10.1007/s10291-014-0435-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81787 [article]

Outputs from the general development project in 2011-2014 towards the realization of multi-GNSS surveying in Japan / Hiromichi Tsuji in Bulletin of the GeoSpatial Information authority of Japan, vol 63 (December 2015)

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Street smart: 3-D city mapping and modeling for positioning with multi-GNSS / Li-Ta Hsu in GPS world, vol 26 n° 7 (July 2015)  

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IGS-MGEX, on prépare le terrain pour les sciences et techniques GNSS multi-constellation / Olivier Montenbruck in XYZ, n° 140 (septembre - novembre 2014)

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Modernization of GEONET from GPS to GNSS / Hiromichi Tsuji in Bulletin of the GeoSpatial Information authority of Japan, vol 61 (December 2013)

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Development status of the World's GNSS and the trend of the satellite positioning utilization / M. Nakamura in Journal of the National institute of information and communications technology, vol 57 n°3-4 (September - december 2010)  

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Shifting satellites: GNSS update / H. Lekkerkerk in Geoinformatics, vol 13 n° 1 (01/01/2010)

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