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Enhanced local ionosphere model for multi-constellations single frequency precise point positioning applications: Egyptian case study / Emad El Manaily in Artificial satellites, vol 53 n° 4 (December 2018)    

Public [article]  inArtificial satellites > vol 53 n° 4 (December 2018) . - pp.141 – 157 Titre : Enhanced local ionosphere model for multi-constellations single frequency precise point positioning applications: Egyptian case study Type de document : Article/Communication Auteurs : Emad El Manaily, Auteur ; Mahmoud Abd Rabbou, Auteur ; Adel El-Shazly, Auteur ; Moustafa Baraka, Auteur Année de publication : 2018 Article en page(s) : pp.141 – 157 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] constellation GNSS [Termes IGN] Egypte [Termes IGN] international GPS service for geodynamics [Termes IGN] Le Caire [Termes IGN] modèle ionosphérique [Termes IGN] occultation du signal [Termes IGN] positionnement par GNSS [Termes IGN] positionnement ponctuel précis [Termes IGN] récepteur monofréquence [Termes IGN] retard ionosphèrique [Termes IGN] signal GNSS Résumé : (auteur) The positioning accuracy of single frequency precise point positioning (SFPPP) attributes mainly to the ionosphere error, which strongly affects GNSS signals. When GNSS signals pass through the various ionosphere layers, they will be bent and their speed will be changed due to dispersive nature of ionosphere. To correct the ionosphere error, it is common to use Klobuchar ionosphere model or Global Ionosphere Maps (GIM). However, Klobuchar can deal with only about 50% of the Ionosphere effect and global Ionosphere maps are often inadequate to describe detailed features of local ionosphere because of limited precision and resolution. In this paper, an enhanced local ionosphere model was developed relying on modeling of measurements from a dense Egyptian permanent tracking GNSS network in order to achieve high precision ionosphere delay correction. The performance of the developed enhanced Egyptian ionosphere model (EIM) was verified through multi-constellations SFPPP accuracy for static and kinematic modes. For static mode, 24 hours multi-constellations datasets collected at three selected stations, Alexandria, Cairo, and Aswan, in Egypt on February 27, 2017, to investigate the performance of the developed local ionospheric model in comparison with the Klobuchar, GIM and ionosphere free models. After session time of half an hour, the results show that the performance of static SFPPP based on the developed Egyptian ionospheric map (EIM) achieved a comparable accuracy WRT using ionosphere free model. While using EIM, achieved an improvements of (38%, 28%, and 42%) and (32%, 10%, and 37%) for accuracy of latitude, longitude, and altitude in comparison with using Klobuchar and GIM models, respectively For kinematic mode, datasets of 2 hours of observations with 1 second sampling rate were logged during vehicular test; the test was carried out on the ring road of the city of Cairo, Egypt, on September 16, 2017. After half an hour of kinematic SFPPP data-processing, the performance of using Egyptian ionospheric map (EIM) for ionosphere delay correction, achieved an improvements of three dimension coordinates of (83%, 47%, and 62%) and (57%, 65%, and 21%) with respect to using Klobuchar model and GIM model, respectively. Numéro de notice : A2018-606 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.2478/arsa-2018-0011 Date de publication en ligne : 11/01/2019 En ligne : https://content.sciendo.com/view/journals/arsa/53/4/article-p141.xml Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92627 [article]

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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)  

Public [article]  inSurvey review > vol 50 n° 361 (July 2018) . - pp 373 - 382 Titre : Comparative analysis of multi-constellation GNSS single-frequency precise point positioning Type de document : Article/Communication Auteurs : Mahmoud Abd Rabbou, Auteur ; Adel El-Shazly, Auteur ; Kamal Ahmed, Auteur Année de publication : 2018 Article en page(s) : pp 373 - 382 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes IGN] analyse comparative [Termes IGN] positionnement par BeiDou [Termes IGN] positionnement par Galileo [Termes IGN] positionnement par GLONASS [Termes IGN] positionnement par GPS [Termes IGN] positionnement ponctuel précis [Termes IGN] récepteur GNSS [Termes IGN] récepteur monofréquence Résumé : (Auteur) We develop new single-frequency PPP models, which combine the observations of the current GNSS constellations, including GPS, GLONASS, Galileo and BeiDou. Four single-frequency GNSS PPP models are developed, namely, the undifferenced single-frequency GNSS PPP model, the undifferenced ionosphere-free (IF) code and phase model known as quasi-phase model, the between-satellite-single-difference model (BSSD) and the between-satellite-single-difference ionosphere-free (BSSDIF) model. The IGS final precise products are used to account for the orbital and clock errors. For both undifferenced and BSSD models, the IGS final global ionospheric maps (GIM) model is used to correct the ionospheric delay. The GNSS inter-system biases are treated as additional unknowns in the estimation process for the undifferenced models, while a loosely coupled technique is used for the BSSD models. Various GNSS combinations are considered in the assessment for each PPP model, including GPS/GLONASS, GPS/Galileo, GPS/BeiDou and quad-constellation GNSS observations. It is shown that the multi-GNSS observations enhance the PPP solution accuracy in comparison with the GPS-only solution. Furthermore, the use of IF-PPP technique enhances the positioning accuracy by 25, 20, 24, 20 and 19% compared with the GIM-based PPP model for the GPS-only, GPS/GLONASS, GPS/Galileo, GPS/BeiDou and quad-GNSS combinations, respectively, for 1 h of GNSS data processing. In addition, an average of 15% positioning accuracy improvement can be obtained when the BSSD techniques are used compared with the undifferenced techniques. However, for 6 h of processing, comparable positioning accuracy can be obtained from all four single-frequency models. Numéro de notice : A2018-445 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2017.1296628 Date de publication en ligne : 13/03/2017 En ligne : https://doi.org/10.1080/00396265.2017.1296628 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91030 [article]

Evaluation of quad-constellation GNSS precise point positioning in Egypt / Emad El Manaily in Artificial satellites, vol 52 n° 1 (March 2017)  

Public [article]  inArtificial satellites > vol 52 n° 1 (March 2017) . - pp 9 - Titre : Evaluation of quad-constellation GNSS precise point positioning in Egypt Type de document : Article/Communication Auteurs : Emad El Manaily, Auteur ; Mahmoud Abd Rabbou, Auteur ; Adel El-Shazly, Auteur ; Moustafa Baraka, Auteur Année de publication : 2017 Article en page(s) : pp 9 - Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] Alexandrie [Termes IGN] Assouan [Termes IGN] Le Caire [Termes IGN] positionnement par BeiDou [Termes IGN] positionnement par Galileo [Termes IGN] positionnement par GNSS [Termes IGN] positionnement ponctuel précis [Termes IGN] zone urbaine Résumé : (auteur) Commonly, relative GPS positioning technique is used in Egypt for precise positioning applications. However, the requirement of a reference station is usually problematic for some applications as it limits the operational range of the system and increases the system cost and complexity. On the other hand, the single point positioning is traditionally used for low accuracy applications such as land vehicle navigation with positioning accuracy up to 10 meters in some scenarios which caused navigation problems especially in downtown areas. Recently, high positioning accuracy can be obtained through Precise Point Positioning (PPP) technique in which only once GNSS receiver is used. However, the major drawback of PPP is the long convergence time to reach to the surveying grade accuracy compared to the existing relative techniques. Moreover, the PPP accuracy is significantly degraded due to shortage in satellite availability in urban areas. To overcome these limitations, the quad constellation GNSS systems namely GPS, GLONASS, Galileo and BeiDou can be combined to increase the satellite availability and enhance the satellite geometry which in turn reduces the convergence time. In Egypt, at the moment, the signals of both Galileo and BeiDou could be logged with limited number of satellites up to four and six satellites for both Systems respectively. In this paper, we investigated the performance of the Quad-GNSS positioning in both dual- and single-frequency ionosphere free PPP modes for both high accurate and low cost navigation application, respectively. The performance of the developed PPP models will be investigated through GNSS data sets collected at three Egyptian cities namely, Cairo, Alexandria and Aswan. Numéro de notice : A2017-268 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/arsa-2017-0002 En ligne : https://doi.org/10.1515/arsa-2017-0002 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85292 [article]

Performance analysis of precise point positioning using multi-constellation GNSS : GPS, GLONASS, Galileo and BeiDou / Mahmoud Abd Rabbou in Survey review, vol 49 n° 352 (March 2017)  

Public [article]  inSurvey review > vol 49 n° 352 (March 2017) . - pp 39 - 50 Titre : Performance analysis of precise point positioning using multi-constellation GNSS : GPS, GLONASS, Galileo and BeiDou Type de document : Article/Communication Auteurs : Mahmoud Abd Rabbou, Auteur ; Ahmed El-Rabbany, Auteur Année de publication : 2017 Article en page(s) : pp 39 - 50 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] combinaison au niveau des observations [Termes IGN] performance [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] positionnement ponctuel précis [Termes IGN] positionnement statique [Termes IGN] précision du positionnement [Termes IGN] simple différence Résumé : (Auteur) We developed a new GNSS PPP model, which combines the observations of GPS, GLONASS, Galileo and BeiDou satellite navigation systems for precise applications. Both undifferenced and between-satellite single-difference (BSSD) ionosphere-free GNSS PPP models are developed. The contribution of the new GNSS observations is assessed compared with the existing GPS and GPS/GLONASS PPP using three-hours GNSS static data positioning results for several GNSS stations and four consecutive days. Inter-system biases between GPS and other GNSS systems are obtained as additional unknowns in the developed PPP filter. The results indicate that both GPS and GPS/Galileo PPP present comparable positioning accuracy level, which is attributed to the limited number of Galileo satellites. The additional BeiDou observations enhances the positioning accuracy after 15 minutes by 5 cm, 4 cm and 9 cm in latitude, longitude and altitude, respectively compared with GPS only positioning accuracy. However, the BeiDou only PPP results present less accurate positioning accuracy compared with the GPS only PPP. The multi-constellation GNSS PPP enhances the positioning accuracy by 8 cm, 6 cm and 11 cm in latitude, longitude and altitude, respectively compared with the GPS PPP results. Compared with the undifferenced PPP results, the BSSD model enhances the positioning accuracy after 15 minutes for the different GNSS constellations based PPP. The GPS/Galileo PPP positioning accuracy improves by 30%, 27% and 10% in latitude, longitude and altitude, respectively and the GPS/BeiDou PPP positioning accuracy, enhances by 17%, 22% and 15% in latitude, longitude and altitude, respectively while the multi-constellation GNSS PPP positioning accuracy improves by 22% and 15% in latitude and altitude, respectively over the undifferenced PPP technique. Additionally, the BSSD model is found to be superior with respect to the convergence times for the different GNSS combinations based PPP over the traditional undifferenced PPP model. Numéro de notice : A2017-058 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1080/00396265.2015.1108068 En ligne : https://doi.org/10.1080/00396265.2015.1108068 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84266 [article]

Single-frequency precise point positioning using multi-constellation GNSS: GPS, Glonass, Galileo and Beidou / Mahmoud Abd Rabbou in Geomatica, vol 70 n° 2 (June 2016)  

Public [article]  inGeomatica > vol 70 n° 2 (June 2016) . - pp 113 - 122 Titre : Single-frequency precise point positioning using multi-constellation GNSS: GPS, Glonass, Galileo and Beidou Type de document : Article/Communication Auteurs : Mahmoud Abd Rabbou, Auteur ; Ahmed El-Rabbany, Auteur Année de publication : 2016 Article en page(s) : pp 113 - 122 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes IGN] constellation GNSS [Termes IGN] modèle ionosphérique [Termes IGN] positionnement par GNSS [Termes IGN] positionnement ponctuel précis Résumé : (auteur) Single-frequency precise point positioning (PPP) presents a cost-effective positioning technique for a large number of users. However, it possesses low positioning accuracy and convergence time compared with the dual-frequency PPP. Single-frequency PPP commonly employs GPS satellite systems that suffer from poor satellite geometry, especially in dense urban areas. We develop a new single-frequency PPP model that combines the observations of current GNSS constellations, including GPS, GLONASS, Galileo and Beidou. The MGEX IGS final precise products are utilized to account for the orbital and clock errors, while the IGS final global ionospheric maps (GIM) model is used to correct for the ionospheric delay. The GNSS inter-system biases are treated as additional unknowns in the estimation process. The contribution of the additional GNSS observations to single-frequency PPP is assessed through solution comparison with its traditional GPS-only counterpart. Various GNSS combinations are considered in the assessment, including GPS/GLONASS, GPS/Galileo, GPS/BeiDou and all-constellation GNSS. It is shown that the additional GNSS observations enhance the PPP solution accuracy and convergence time in comparison with the traditional GPS-only solution. Except for stations with a sufficient number of tracked BeiDou satellites, both Galileo and BeiDou have marginal effects on the positioning accuracy due to their limited number of satellites. However, for stations with a sufficient number of visible BeiDou satellites, an average of 40% PPP accuracy improvement is obtained. The major contribution to the PPP accuracy enhancement is obtained from GLONASS satellite observations. Numéro de notice : A2016-679 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.5623/cig2016-203 En ligne : http://dx.doi.org/10.5623/cig2016-203 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81933 [article]

Tightly coupled integration of GPS precise point positioning and MEMS-based inertial systems / Mahmoud Abd Rabbou in GPS solutions, vol 19 n° 4 (october 2015)  

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