Descripteur
Documents disponibles dans cette catégorie (1802)
Ajouter le résultat dans votre panier
Visionner les documents numériques
Affiner la recherche Interroger des sources externes
Etendre la recherche sur niveau(x) vers le bas
Modeling tropospheric wet delays with national GNSS reference network in China for BeiDou precise point positioning / Fu Zheng in Journal of geodesy, vol 92 n° 5 (May 2018)
[article]
Titre : Modeling tropospheric wet delays with national GNSS reference network in China for BeiDou precise point positioning Type de document : Article/Communication Auteurs : Fu Zheng, Auteur ; Yidong Lou, Auteur ; Shengfeng Gu, Auteur ; Xiaopeng Gong, Auteur ; Chuang Shi, Auteur Année de publication : 2018 Article en page(s) : pp 545 – 560 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] Chine
[Termes IGN] données météorologiques
[Termes IGN] positionnement par BeiDou
[Termes IGN] positionnement par GPS
[Termes IGN] positionnement ponctuel précis
[Termes IGN] propagation troposphérique
[Termes IGN] retard troposphérique zénithal
[Termes IGN] temps réelRésumé : (Auteur) During past decades, precise point positioning (PPP) has been proven to be a well-known positioning technique for centimeter or decimeter level accuracy. However, it needs long convergence time to get high-accuracy positioning, which limits the prospects of PPP, especially in real-time applications. It is expected that the PPP convergence time can be reduced by introducing high-quality external information, such as ionospheric or tropospheric corrections. In this study, several methods for tropospheric wet delays modeling over wide areas are investigated. A new, improved model is developed, applicable in real-time applications in China. Based on the GPT2w model, a modified parameter of zenith wet delay exponential decay wrt. height is introduced in the modeling of the real-time tropospheric delay. The accuracy of this tropospheric model and GPT2w model in different seasons is evaluated with cross-validation, the root mean square of the zenith troposphere delay (ZTD) is 1.2 and 3.6 cm on average, respectively. On the other hand, this new model proves to be better than the tropospheric modeling based on water-vapor scale height; it can accurately express tropospheric delays up to 10 km altitude, which potentially has benefits in many real-time applications. With the high-accuracy ZTD model, the augmented PPP convergence performance for BeiDou navigation satellite system (BDS) and GPS is evaluated. It shows that the contribution of the high-quality ZTD model on PPP convergence performance has relation with the constellation geometry. As BDS constellation geometry is poorer than GPS, the improvement for BDS PPP is more significant than that for GPS PPP. Compared with standard real-time PPP, the convergence time is reduced by 2–7 and 20–50% for the augmented BDS PPP, while GPS PPP only improves about 6 and 18% (on average), in horizontal and vertical directions, respectively. When GPS and BDS are combined, the geometry is greatly improved, which is good enough to get a reliable PPP solution, the augmentation PPP improves insignificantly comparing with standard PPP. Numéro de notice : A2018-148 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-017-1080-4 Date de publication en ligne : 29/10/2017 En ligne : https://doi.org/10.1007/s00190-017-1080-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89759
in Journal of geodesy > vol 92 n° 5 (May 2018) . - pp 545 – 560[article]Assessment of the possible contribution of space ties on-board GNSS satellites to the terrestrial reference frame / Sara Bruni in Journal of geodesy, vol 92 n° 4 (April 2018)
[article]
Titre : Assessment of the possible contribution of space ties on-board GNSS satellites to the terrestrial reference frame Type de document : Article/Communication Auteurs : Sara Bruni, Auteur ; Paul Rebischung , Auteur ; Susanna Zerbini, Auteur ; Zuheir Altamimi , Auteur ; Maddalena Errico, Auteur ; Efisio Santi, Auteur Année de publication : 2018 Projets : 3-projet - voir note / Article en page(s) : pp 383 - 399 Note générale : bibliographie
This work was performed under grant ECOCZE RB from the Università di Bologna.Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] point de liaison (géodésie)
[Termes IGN] positionnement par GNSS
[Termes IGN] positionnement par télémétrie laser sur satelliteRésumé : (auteur) The realization of the international terrestrial reference frame (ITRF) is currently based on the data provided by four space geodetic techniques. The accuracy of the different technique-dependent materializations of the frame physical parameters (origin and scale) varies according to the nature of the relevant observables and to the impact of technique-specific errors. A reliable computation of the ITRF requires combining the different inputs, so that the strengths of each technique can compensate for the weaknesses of the others. This combination, however, can only be performed providing some additional information which allows tying together the independent technique networks. At present, the links used for that purpose are topometric surveys (local/terrestrial ties) available at ITRF sites hosting instruments of different techniques. In principle, a possible alternative could be offered by spacecrafts accommodating the positioning payloads of multiple geodetic techniques realizing their co-location in orbit (space ties). In this paper, the GNSS–SLR space ties on-board GPS and GLONASS satellites are thoroughly examined in the framework of global reference frame computations. The investigation focuses on the quality of the realized physical frame parameters. According to the achieved results, the space ties on-board GNSS satellites cannot, at present, substitute terrestrial ties in the computation of the ITRF. The study is completed by a series of synthetic simulations investigating the impact that substantial improvements in the volume and quality of SLR observations to GNSS satellites would have on the precision of the GNSS frame parameters. Numéro de notice : A2018-050 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-017-1069-z Date de publication en ligne : 06/10/2017 En ligne : https://doi.org/10.1007/s00190-017-1069-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89354
in Journal of geodesy > vol 92 n° 4 (April 2018) . - pp 383 - 399[article]Carrier phase bias estimation of geometry-free linear combination of GNSS signals for ionospheric TEC modeling / Anna Krypiak-Gregorczyk in GPS solutions, vol 22 n° 2 (April 2018)
[article]
Titre : Carrier phase bias estimation of geometry-free linear combination of GNSS signals for ionospheric TEC modeling Type de document : Article/Communication Auteurs : Anna Krypiak-Gregorczyk, Auteur ; Pawel Wielgosz, Auteur Année de publication : 2018 Article en page(s) : pp 22 - 45 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] combinaison linéaire
[Termes IGN] erreur systématique
[Termes IGN] modèle ionosphérique
[Termes IGN] phase
[Termes IGN] positionnement par GNSS
[Termes IGN] retard ionosphèrique
[Termes IGN] signal GNSS
[Termes IGN] teneur totale en électrons
[Vedettes matières IGN] Traitement de données GNSSRésumé : (Auteur) The ionosphere can be modeled and studied using multi-frequency GNSS signals and their geometry-free linear combination. Therefore, a number of GNSS-derived ionospheric models have been developed and applied in a broad range of applications. However, due to the complexity of estimating the carrier phase ambiguities, most of these models are based on low-accuracy carrier phase smoothed pseudorange data. This, in turn, critically limits their accuracy and applicability. Therefore, we present a new methodology of estimating the phase bias of the scaled L1 and L2 carrier phase difference which is a function of the ambiguities, the ionospheric delay, and hardware delays. This methodology is suitable for ionospheric modeling at regional and continental scales. In addition, we present its evaluation under varying ionospheric conditions. The test results show that the carrier phase bias of geometry-free linear combination can be estimated with a very high accuracy, which consequently allows for calculating ionospheric TEC with the uncertainty lower than 1.0 TECU. This high accuracy makes the resulting ionosphere model suitable for improving GNSS positioning for high-precision applications in geosciences. Numéro de notice : A2018-160 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-018-0711-4 Date de publication en ligne : 16/02/2018 En ligne : https://doi.org/10.1007/s10291-018-0711-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89783
in GPS solutions > vol 22 n° 2 (April 2018) . - pp 22 - 45[article]Kinematic-PPP using single/dual frequency observations from (GPS, GLONASS and GPS/GLONASS) constellations for hydrography / Ashraf Farah in Artificial satellites, vol 53 n° 1 (March 2018)
[article]
Titre : Kinematic-PPP using single/dual frequency observations from (GPS, GLONASS and GPS/GLONASS) constellations for hydrography Type de document : Article/Communication Auteurs : Ashraf Farah, Auteur Année de publication : 2018 Article en page(s) : pp 37 - 46 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Assouan
[Termes IGN] données GLONASS
[Termes IGN] données GPS
[Termes IGN] Nil (fleuve)
[Termes IGN] positionnement cinématique
[Termes IGN] positionnement par GLONASS
[Termes IGN] positionnement par GPS
[Termes IGN] positionnement ponctuel précis
[Termes IGN] récepteur bifréquence
[Termes IGN] récepteur monofréquenceRésumé : (auteur) Global Positioning System (GPS) technology is ideally suited for inshore and offshore positioning because of its high accuracy and the short observation time required for a position fix. Precise point positioning (PPP) is a technique used for position computation with a high accuracy using a single GNSS receiver. It relies on highly accurate satellite position and clock data that can be acquired from different sources such as the International GNSS Service (IGS). PPP precision varies based on positioning technique (static or kinematic), observations type (single or dual frequency) and the duration of observations among other factors. PPP offers comparable accuracy to differential GPS with safe in cost and time. For many years, PPP users depended on GPS (American system) which considered the solely reliable system. GLONASS's contribution in PPP techniques was limited due to fail in maintaining full constellation. Yet, GLONASS limited observations could be integrated into GPS-based PPP to improve availability and precision. As GLONASS reached its full constellation early 2013, there is a wide interest in PPP systems based on GLONASS only and independent of GPS. This paper investigates the performance of kinematic PPP solution for the hydrographic applications in the Nile river (Aswan, Egypt) based on GPS, GLONASS and GPS/GLONASS constellations. The study investigates also the effect of using two different observation types; single-frequency and dual frequency observations from the tested constellations. Numéro de notice : A2018-174 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.2478/arsa-2018-0004 Date de publication en ligne : 24/03/2018 En ligne : https://doi.org/10.2478/arsa-2018-0004 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89814
in Artificial satellites > vol 53 n° 1 (March 2018) . - pp 37 - 46[article]Reduction of ZTD outliers through improved GNSS data processing and screening strategies [Interactive discussion] / Katarzyna Stępniak in Atmospheric measurement techniques, vol 11 n° 3 (March 2018)
[article]
Titre : Reduction of ZTD outliers through improved GNSS data processing and screening strategies [Interactive discussion] Type de document : Article/Communication Auteurs : Katarzyna Stępniak, Auteur ; Olivier Bock , Auteur ; Pawel Wielgosz, Auteur Année de publication : 2018 Projets : 3-projet - voir note / Article en page(s) : pp 1347 - 1361 Note générale : Bibliographie
This work has been supported by Polish National Science Centre grant no. UMO-2015/19/B/ST10/02758. The study was partially carried out during Short Term Scientific Mission (STSM) in the framework of ES1206 COST Action.Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] Bernese
[Termes IGN] coordonnées GPS
[Termes IGN] double différence
[Termes IGN] erreur systématique
[Termes IGN] Pologne
[Termes IGN] réseau géodésique local
[Termes IGN] réseau géodésique permanent
[Termes IGN] retard troposphérique zénithal
[Termes IGN] série temporelle
[Termes IGN] valeur aberranteRésumé : (Auteur) Though Global Navigation Satellite System (GNSS) data processing has been significantly improved over the years, it is still commonly observed that zenith tropospheric delay (ZTD) estimates contain many outliers which are detrimental to meteorological and climatological applications. In this paper, we show that ZTD outliers in double-difference processing are mostly caused by sub-daily data gaps at reference stations, which cause disconnections of clusters of stations from the reference network and common mode biases due to the strong correlation between stations in short baselines. They can reach a few centimetres in ZTD and usually coincide with a jump in formal errors. The magnitude and sign of these biases are impossible to predict because they depend on different errors in the observations and on the geometry of the baselines. We elaborate and test a new baseline strategy which solves this problem and significantly reduces the number of outliers compared to the standard strategy commonly used for positioning (e.g. determination of national reference frame) in which the pre-defined network is composed of a skeleton of reference stations to which secondary stations are connected in a star-like structure. The new strategy is also shown to perform better than the widely used strategy maximizing the number of observations available in many GNSS programs. The reason is that observations are maximized before processing, whereas the final number of used observations can be dramatically lower because of data rejection (screening) during the processing. The study relies on the analysis of 1 year of GPS (Global Positioning System) data from a regional network of 136 GNSS stations processed using Bernese GNSS Software v.5.2. A post-processing screening procedure is also proposed to detect and remove a few outliers which may still remain due to short data gaps. It is based on a combination of range checks and outlier checks of ZTD and formal errors. The accuracy of the final screened GPS ZTD estimates is assessed by comparison to ERA-Interim reanalysis. Numéro de notice : A2018-065 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.5194/amt-11-1347-2018 Date de publication en ligne : 08/03/2018 En ligne : http://dx.doi.org/10.5194/amt-11-1347-2018 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89407
in Atmospheric measurement techniques > vol 11 n° 3 (March 2018) . - pp 1347 - 1361[article]Le réseau et les services Orphéon intègrent Galileo et BeiDou : quels sont les avantages pour le NRTK de haute précision ? / Xiaoguang Luo in XYZ, n° 154 (mars - mai 2018)PermalinkAirborne laser scanning for tree diameter distribution modelling: a comparison of different modelling alternatives in a tropical single-species plantation / Matti Maltamo in Forestry, an international journal of forest research, vol 91 n° 1 (January 2018)PermalinkPermalinkAn accurate Kriging-based regional ionospheric model using combined GPS/BeiDou observations / Mohamed Abdelazeem in Journal of applied geodesy, vol 12 n° 1 (January 2018)PermalinkL'analyse des performance RTK dans la zone urbaine / Mohamed Hamza Megrerouche in Bulletin des sciences géographiques, n° 31 (2017 - 2018)PermalinkBruit de scintillation dans les séries temporelles de positions GNSS : origines et conséquences / Paul Rebischung (2018)PermalinkDesign and implementation of a model predictive observer for AHRS / Jafar Keighobadi in GPS solutions, vol 22 n° 1 (January 2018)PermalinkMixed integer–real least squares estimation for precise GNSS positioning using a modified ambiguity function approach / Krzysztof Nowel in GPS solutions, vol 22 n° 1 (January 2018)PermalinkPermalinkPermalink