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Multi-GNSS real-time precise clock estimation considering the correction of inter-satellite code biases / Liang Chen in GPS solutions, vol 25 n° 2 (April 2021)  

Public [article]  inGPS solutions > vol 25 n° 2 (April 2021) . - 17 p. Titre : Multi-GNSS real-time precise clock estimation considering the correction of inter-satellite code biases Type de document : Article/Communication Auteurs : Liang Chen, Auteur ; Min Li, Auteur ; Ying Zhao, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : 17 p. Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] correction [Termes IGN] décalage d'horloge [Termes IGN] erreur systématique inter-systèmes [Termes IGN] phase [Termes IGN] positionnement par BeiDou [Termes IGN] positionnement par Galileo [Termes IGN] positionnement par GLONASS [Termes IGN] positionnement par GNSS [Termes IGN] positionnement par GPS [Termes IGN] récepteur GNSS [Termes IGN] temps réel Résumé : (Auteur) For reasons mostly related to chip shape distortions, global navigation satellite system (GNSS) observations are corrupted by receiver-dependent biases. These are often stable in the long term, though numerically different depending on the signal frequency, satellite system and receiver manufacturer. Based on the mixed-differenced model combining undifferenced pseudorange with epoch-differenced carrier phase observations, we present a multi-GNSS real-time precise clock estimation model considering correction of inter-satellite code biases (ISCBs). Pre-estimated receiver-dependent ISCB corrections are introduced to correct the inter-receiver, inter-satellite and inter-system biases largely. Then the number of estimated parameters is reduced to a manageable level for real-time estimation. Comparisons with post-processed data show that compared to undifferenced, epoch-differenced and non-bias-corrected mixed-differenced models, the proposed bias-corrected model can greatly reduce the precise clock offset systematic biases, especially for GLONASS and BeiDou. The test results show the root mean square data reductions are improved by up to 96% for GLONASS, 78% for BeiDou and 40% for GPS and Galileo. Numéro de notice : A2021-092 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-020-01065-z date de publication en ligne : 15/01/2021 En ligne : https://doi.org/10.1007/s10291-020-01065-z Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96883 [article]

Application of baseline constraint Kalman filter to BeiDou precise point positioning / Xiaoguo Guan in Survey review, vol 53 n°376 (January 2021)  

Public [article]  inSurvey review > vol 53 n°376 (January 2021) . - pp 55 - 69 Titre : Application of baseline constraint Kalman filter to BeiDou precise point positioning Type de document : Article/Communication Auteurs : Xiaoguo Guan, Auteur ; Hongzhou Chai, Auteur ; Guorui Xiao, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : pp 55 - 69 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] filtre de Kalman [Termes IGN] géodésie marine [Termes IGN] ligne de base [Termes IGN] positionnement cinématique [Termes IGN] positionnement par BeiDou [Termes IGN] positionnement ponctuel précis [Termes IGN] positionnement statique [Termes IGN] précision du positionnement Résumé : (auteur) This paper proposes a baseline constrained PPP method to enhance the performance. The approach is based on constrained Kalman filter, and applied to BeiDou PPP in static, pseudo-kinematic, real kinematic modes. Both zero baseline and short baseline constrained PPP are verified in static mode, while a marine geodesy environment is designed to evaluate the performance in kinematic mode. The experiment results show that, compared to the PPP without constraint, the baseline constrained PPP can significantly improve the positional accuracy. Furthermore, the accuracy of baseline constrained static PPP can reach centimetre level, while the kinematic PPP can reach decimetre level. Numéro de notice : A2021-049 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2019.1685197 date de publication en ligne : 07/11/2019 En ligne : https://doi.org/10.1080/00396265.2019.1685197 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96784 [article]

A multi-frequency and multi-GNSS method for the retrieval of the ionospheric TEC and intraday variability of receiver DCBs / Min Li in Journal of geodesy, vol 94 n° 10 (October 2020)  

Public [article]  inJournal of geodesy > vol 94 n° 10 (October 2020) . - 14 p. Titre : A multi-frequency and multi-GNSS method for the retrieval of the ionospheric TEC and intraday variability of receiver DCBs Type de document : Article/Communication Auteurs : Min Li, Auteur ; Yunbin Yuan, Auteur ; Xiao Zhang, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : 14 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] erreur systématique [Termes IGN] fréquence multiple [Termes IGN] modèle ionosphérique [Termes IGN] positionnement différentiel [Termes IGN] positionnement par BeiDou [Termes IGN] récepteur GNSS [Termes IGN] teneur totale en électrons [Termes IGN] variation diurne Résumé : (auteur) As one of the important factors influencing the ionospheric total electron content (TEC) estimation accuracy, receiver differential code biases (DCBs) should be properly removed from global navigation satellite system (GNSS) measurements. The intraday variability in receiver DCBs (rDCBs), which is usually ignored in the commonly used ionospheric observable retrieval procedure, has been identified as one of the major errors degrading the accuracy of TEC estimation. The modified carrier-to-code leveling (MCCL) method can be adopted to eliminate the impact of the rDCB variability on the retrieval of the ionospheric TEC from dual-frequency (DF) GNSS observations. In this contribution, we extend the MCCL method from two aspects. First, the DF MCCL method is adapted to the multi-frequency (MF) case, in which DF, triple-frequency or even arbitrary-frequency observations can be readily processed to simultaneously estimate both the ionospheric TEC and rDCB variations. Second, the MCCL method is refined to enable the handling of GLONASS data by accounting for the effects of code inter-frequency biases induced by the frequency division multiple access (FDMA) technology. Based on the test results, the retrieval accuracy of the ionospheric TEC using our proposed method can be improved from 9.47 TECu to 2.67 TECu in the presence of significant intraday rDCB variations. We discovered that the maximum difference in the rDCB variations of the same satellite system between different frequency bands can be as large as 10 ns. The dependence of multi-GNSS and MF rDCB variations on the ambient temperature is further verified in this study. The results show that the temperature dependence of rDCB varies among different satellite systems and frequency bands. Compared to the Galileo, GPS and GLONASS satellite systems, the Beidou system (BDS) rDCB estimates exhibit a stronger correlation with the measured temperature. The percentages of stations with the mean absolute Pearson correlation coefficient value above 0.8 are 27.17% for GPS, 30.58% for GLONASS, 43.78% for BDS and 33.9% for Galileo, respectively. Numéro de notice : A2020-650 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-020-01437-w date de publication en ligne : 12/10/2020 En ligne : https://doi.org/10.1007/s00190-020-01437-w Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96083 [article]

Performance of BDS triple-frequency positioning based on the modified TCAR method / Yijun Tian in Survey review, vol 52 n° 374 (August 2020)  

Public [article]  inSurvey review > vol 52 n° 374 (August 2020) . - pp 415 - 422 Titre : Performance of BDS triple-frequency positioning based on the modified TCAR method Type de document : Article/Communication Auteurs : Yijun Tian, Auteur ; Lifen Sui, Auteur ; Dongqing Zhao, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : pp 415 - 422 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] compensation Lambda [Termes IGN] filtre de Kalman [Termes IGN] positionnement par BeiDou [Termes IGN] précision du positionnement [Termes IGN] résolution d'ambiguïté [Termes IGN] retard ionosphèrique [Termes IGN] triple différence Résumé : (auteur) A modified TCAR method to improve the NL ambiguity resolution over medium-long baseline is presented. The estimated DD ionospheric delay derived from the Kalman-filter floating solution is adopted to modify the floating NL ambiguities. Modified by the smooth DD ionospheric delay, the NL ambiguity residuals are mostly within 0.5 cycles over medium-long baselines, showing a significant improvement in contrast to the classical TCAR method. The positioning performances of the modified method are even better than the LAMBDA method over 72 and 634 km baselines. As the ambiguity can be correctly fixed just after several epochs, high-precision positioning can be achieved in a very short time. Numéro de notice : A2020-517 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2019.1627507 date de publication en ligne : 12/06/2019 En ligne : https://doi.org/10.1080/00396265.2019.1627507 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95677 [article]

Effect of spatial correlation on the performances of modernized GPS and Galileo in relative positioning / Noureddine Kheloufi in Geodesy and cartography, vol 46 n° 2 (July 2020)  

Public [article]  inGeodesy and cartography > vol 46 n° 2 (July 2020) . - pp 89 - 97 Titre : Effect of spatial correlation on the performances of modernized GPS and Galileo in relative positioning Type de document : Article/Communication Auteurs : Noureddine Kheloufi, Auteur ; Abdelhalim Niati, Auteur Année de publication : 2020 Article en page(s) : pp 89 - 97 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] compensation Lambda [Termes IGN] corrélation automatique de points homologues [Termes IGN] double différence [Termes IGN] estimation de quantité [Termes IGN] fréquence multiple [Termes IGN] ligne de base [Termes IGN] modèle stochastique [Termes IGN] positionnement différentiel [Termes IGN] positionnement par BeiDou [Termes IGN] positionnement par Galileo [Termes IGN] positionnement par GPS [Termes IGN] résolution d'ambiguïté [Termes IGN] retard ionosphèrique Résumé : (auteur) In the context of processing GNSS (Global Navigation Satellite System) data, it is known that the estimation of the ionospheric delays decreases the strength of the observation model and makes significant the time required to fix the ambiguities namely in case of long baselines. However, considering the double-differenced (DD) ionospheric delays as stochastic quantities, the redundancy in this case increases and leads to the reduction of time of fixing the ambiguities. The approach developed in the present paper makes two considerations: 1) the DD ionospheric delays are assumed as stochastic quantities and, 2) the spatial correlation of errors is accounted for based on a simple model of correlation. A simulation is made and aims to study the effect of these two mentioned considerations on the performances of the three multifrequency GNSSs; modernized GPS, Galileo and BDS which are not yet in full capability. For each GNSS, dual-frequency combinations of frequencies as well as triple-frequency combination are investigated in the simulation. The performances studied include: the time to fix the ambiguities with high success rate and the precision of coordinates in static relative positioning with varying baseline length. A method is developed to derive what we call the spatial correlation model which approximately gives the covariance between the individual errors belonging to two stations. Furthermore, the stochastic models that follow from accounting and neglecting the spatial correlation are developed. The LAMBDA (Least-squares Ambiguity Decorrelation Adjustment) method is implemented for ambiguity decorrelation. The results show that the time to fix the ambiguities caused by accounting the spatial correlation is less than the time of fix without the spatial correlation. Also, a slight superiority of Galileo in terms of performances is seen compared to the other GNSS. For all the dualfrequency combinations investigated, when processing a baseline length of 500 km with accounted spatial correlation, the time needed to successfully fix the ambiguities lies between 5 and 9 min, whereas it becomes only between 2.5 and 3 min for all the triple-frequency combinations, this is with a sampling time of 5 s. In addition, for all different combinations, the coordinates precision is less than 8 mm even for 500 km. We think that these high performances result from: 1) the precise codes of future GNSS signals, 2) the high redundancy in the observations equation and, 3) taking into account the spatial correlation in the definition of the stochastic model. Numéro de notice : A2020-781 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3846/gac.2020.11009 date de publication en ligne : 15/07/2020 En ligne : https://doi.org/10.3846/gac.2020.11009 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96475 [article]

GPS + Galileo + BeiDou precise point positioning with triple-frequency ambiguity resolution / Pan Li in GPS solutions, Vol 24 n° 3 (July 2020)  

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Real-time clock prediction of multi-GNSS satellites and its application in precise point positioning / Yaquan Peng in Advances in space research, vol 64 n°7 (1 October 2019)  

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Landslide monitoring analysis of single-frequency BDS/GPS combined positioning with constraints on deformation characteristics / Dongwei Qiu in Survey review, vol 51 n° 367 (July 2019)  

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Accounting for the differential inter-system bias (DISB) of code observation in GPS+BDS positioning / Xiang Cao in Journal of applied geodesy, vol 13 n° 1 (January 2019)  

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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)  

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Real-time capturing of seismic waveforms using high-rate BDS, GPS and GLONASS observations: the 2017 Mw 6.5 Jiuzhaigou earthquake in China / Xingxing Li in GPS solutions, vol 23 n° 1 (January 2019)  

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Comparative analysis of multi-constellation GNSS single-frequency precise point positioning / Mahmoud Abd Rabbou in Survey review, vol 50 n° 361 (July 2018)  

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Multi-GNSS phase delay estimation and PPP ambiguity resolution : GPS, BDS, GLONASS, Galileo / Xingxing Li in Journal of geodesy, vol 92 n° 6 (June 2018)  

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Performance of absolute real-time multi-GNSS kinematic positioning / Kamil Kazmierski in Artificial satellites, vol 53 n° 2 (June 2018)    

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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)  

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