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A novel approach to design measurement models of single-frequency GPS receivers for cost-effective structural monitoring networks / H. Lee in Survey review, vol 49 n° 354 (September 2017)  

Public [article]  inSurvey review > vol 49 n° 354 (September 2017) . - pp 160 - 170 Titre : A novel approach to design measurement models of single-frequency GPS receivers for cost-effective structural monitoring networks Type de document : Article/Communication Auteurs : H. Lee, Auteur ; J.O. Lee, Auteur ; A. Musa, Auteur ; H.-Y. Chen, Auteur Année de publication : 2017 Article en page(s) : pp 160 - 170 Note générale : Bibliographie Langues : Anglais (eng) Résumé : (Auteur) The global positioning system (GPS) has become an effective tool for measuring the dynamics of engineering structures from their absolute displacements. Although dual-frequency GPS receivers are widely adopted for structural monitoring applications to guarantee coordinate accuracy of the order of a few centimetres, the associated cost is too high to place larger number of these sensors. It has been recently recognised that single-frequency GPS receivers have great potential to be the smart sensors for measuring structural displacement due to their low-cost, small form-factor and low power consumption. Hence, the structural monitoring using single-frequency GPS receivers provides a much more cost-effective and compact tool for these applications; however, it remains a challenge to resolve the ambiguities rapidly and reliably. To address such a technical issue, this research focuses on design of GPS measurement models that can be effectively implemented in the structural monitoring networks. The main feature of these models is that they simultaneously model all available observables within the network, including not only GPS satellite ranging signals but also some dynamic constraints of structural monitoring networks, such as nominal coordinates and baselines of the target antennas. A series of tests has been carried out, using simulated satellite geometries and measurements, to assess impact of the proposed models on kinematic positioning performance. The results indicate that overall performance of the models that employ the single-frequency GPS observables and the dynamic constraints can be significantly improved by employing the redundant measurements. Numéro de notice : A2017-542 Affiliation des auteurs : non IGN Nature : Article DOI : 10.1080/00396265.2016.1140394 En ligne : https://doi.org/10.1080/00396265.2016.1140394 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86597 [article]

A robust weighted total least-squares solution with Lagrange multipliers / X. Gong in Survey review, vol 49 n° 354 (September 2017)  

Public [article]  inSurvey review > vol 49 n° 354 (September 2017) . - pp 176 - 185 Titre : A robust weighted total least-squares solution with Lagrange multipliers Type de document : Article/Communication Auteurs : X. Gong, Auteur ; Z. Li, Auteur Année de publication : 2017 Article en page(s) : pp 176 - 185 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse numérique [Termes IGN] méthode des moindres carrés [Termes IGN] méthode robuste [Termes IGN] pondération [Termes IGN] régression [Termes IGN] régression linéaire [Termes IGN] transformation de coordonnées Résumé : (Auteur) Weighted total least-squares (WTLS) is becoming popular for parameter estimations in geodesy and surveying. However, it does not take into consideration the possible gross errors in observations, which may lead to a reduction in the robustness and reliability of parameter estimations. In order to solve this problem, in this study, Lagrange multipliers (LM) are employed to make WTLS solution rigorous and the IGG (Institute of Geodesy and Geophysics) weight function is employed to make WTLS solution more robust and reliable, resulting in a new robust WTLS solution (RWTLS-LM-IGG). A comparison with existing WTLS and robust WTLS solutions is conducted for linear regression and coordinate transformation, through experimental evaluation with simulation data sets (with different numbers and magnitudes of gross errors) and two sets of real-life data. The results of simulation experiments show that the variance component and the mean square error of estimated parameter vector obtained by using the existing methods increase almost linearly with an increase in the numbers and magnitudes of gross errors, but these values obtained by using the proposed method are almost stable, which means an effective reduction of the influence of the gross errors by the proposed method as compared with the existing methods. It is also found that the larger the numbers and magnitudes of gross errors, the more obvious such a reduction. Furthermore, the experiment results with two sets of real-life data are consistent with the results of simulation experiments. Numéro de notice : A2017-543 Affiliation des auteurs : non IGN Thématique : MATHEMATIQUE/POSITIONNEMENT Nature : Article DOI : 10.1080/00396265.2016.1150088 En ligne : https://doi.org/10.1080/00396265.2016.1150088 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86598 [article]

Assessing the performance of multi-GNSS precise point positioning in Asia-Pacific region / X. Zhao in Survey review, vol 49 n° 354 (September 2017)  

Public [article]  inSurvey review > vol 49 n° 354 (September 2017) . - pp 186 - 196 Titre : Assessing the performance of multi-GNSS precise point positioning in Asia-Pacific region Type de document : Article/Communication Auteurs : X. Zhao, Auteur ; S. Wang, Auteur ; C. Liu, Auteur ; J. Ou, Auteur ; X. Yu, Auteur Année de publication : 2017 Article en page(s) : pp 186 - 196 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] Asie (géographie politique) [Termes IGN] données BeiDou [Termes IGN] données GLONASS [Termes IGN] données GPS [Termes IGN] filtre de Kalman [Termes IGN] modèle stochastique [Termes IGN] Pacifique (océan) [Termes IGN] positionnement ponctuel précis [Termes IGN] test de performance Résumé : (Auteur) Multi-Global Navigation Satellite System (GNSS) integration can effectively improve the satellite geometry strength, and certain effect on the precise point positioning (PPP) accuracy and convergence speed. Taking the system difference into account, this paper deduces the unified GNSS observation model, which is extended to the multi-GNSS PPP functional model. Meanwhile, the stochastic model used in Kalman filter parameter estimation is presented in the paper. Furthermore, to evaluate the performance of the multi-GNSS PPP in Asia-Pacific region, observed data from the International GNSS Service reference stations are analysed using the self-developed software. In detail, the results from Global Positioning System (GPS)-, GLObal NAvigation Satellite System (GLONASS)- and BeiDou Navigation Satellite System (BDS)-only PPP, double combined PPP and GPS/GLONASS/BDS combined PPP under the different observation duration and cut-off elevation angles are analysed. Results demonstrate: (1) compared with the single system PPP, the convergence speed of the multi-GNSS PPP is improved while the accuracy is not significantly improved after processing the 24-h data set; (2) when the observation duration is short, such as 0.5 h, the mean convergence percentage of the BDS combined with GPS and GLONASS PPP increases by an average of 49.6% compared with the single individual systems except for BDS, respectively, under the cut-off angle of 5° and (3) when PPP positioning with high cut-off elevation angles, and at the point of centimetre-level positioning, the GPS/GLONASS/BDS combined PPP has a better performance on the convergence percentage and convergence speed. For example, the percentages of the position biases within 0–5 cm for GPS/GLONASS/BDS are increased by 7.2 and 4.5% in North and East direction compared with GPS/GLONASS under the cut-off angle of 35°, more than any other. And the mean convergence time is only 14.5 min. Numéro de notice : A2017-544 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1080/00396265.2016.1151576 En ligne : https://doi.org/10.1080/00396265.2016.1151576 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86599 [article]

Performance evaluation of single-frequency point positioning with GPS, GLONASS, BeiDou and Galileo / L. Pan in Survey review, vol 49 n° 354 (September 2017)  

Public [article]  inSurvey review > vol 49 n° 354 (September 2017) . - pp 197 - 205 Titre : Performance evaluation of single-frequency point positioning with GPS, GLONASS, BeiDou and Galileo Type de document : Article/Communication Auteurs : L. Pan, Auteur ; Changsheng Cai, Auteur ; Rock Santerre, Auteur ; X. Zhang, Auteur Année de publication : 2017 Article en page(s) : pp 197 - 205 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [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 monofréquence [Termes IGN] test de performance Résumé : (Auteur) The single point positioning (SPP) mode has been widely used in many fields such as vehicle navigation, Geographic Information System and land surveying. For a long period, the SPP technology mainly relies on GPS system. With the recent revitalisation of the GLONASS constellation and two newly emerging constellations of BeiDou and Galileo, it is now feasible to investigate the performance of quad-constellation integrated SPP (QISPP) with GPS, GLONASS, BeiDou and Galileo measurements. As a satellite-based positioning technology, the QISPP is expected to improve the accuracy and availability of positioning solutions due to the increased number of visible satellites and the improved satellite sky distribution. In this study, a QISPP model is presented to simultaneously process observations from all four Global Navigation Satellite System (GNSS) constellations. Datasets collected at 47 globally distributed Multi-GNSS Experiment (MGEX) stations on two consecutive days and a kinematic experimental dataset are employed to fully assess the QISPP performance in terms of positioning accuracy and availability. Given that most navigation users are using single-frequency receivers, only the observations on a single frequency are utilised. The results indicate that the QISPP improves the positioning accuracy by an average of 16, 13 and 12% using the MGEX datasets, and 43, 31 and 51% using the kinematic experimental dataset over the GPS-only case in the east, north and up components, respectively. The availability of the QISPP solutions remains 100% even for a mask elevation angle of 40°, whereas it is only 37% for the GPS-only case. All these results are achieved using geodetic-type receivers and they are possibly optimistic for users who use navigation-type receivers. Numéro de notice : A2017-545 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1080/00396265.2016.1151628 En ligne : https://doi.org/10.1080/00396265.2016.1151628 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86600 [article]

TotalStation/GNSS/EGM integrated geocentric positioning method / Edward Osada in Survey review, vol 49 n° 354 (September 2017)  

Public [article]  inSurvey review > vol 49 n° 354 (September 2017) . - pp 206 - 211 Titre : TotalStation/GNSS/EGM integrated geocentric positioning method Type de document : Article/Communication Auteurs : Edward Osada, Auteur ; M. Owczarek-Wesołowska, Auteur ; M. Ficner, Auteur ; G. Kurpiński, Auteur Année de publication : 2017 Article en page(s) : pp 206 - 211 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] coordonnées cartésiennes géocentriques [Termes IGN] déviation de la verticale [Termes IGN] Earth Gravity Model 2008 [Termes IGN] ellipsoïde GRS 1980 [Termes IGN] modélisation 3D [Termes IGN] positionnement par GNSS [Termes IGN] tachéomètre électronique Résumé : (Auteur) In this study, we have investigated the use of the plumb line direction from Global Gravity Earth Model EGM2008 in the 3D integrated TotalStation/GNSS positioning. Our study shows that measurements along a total station traverse provides more accurate positioning results if the vertical deflection of plumb line is retrieved from EGM2008, than positioning with unknown deflection. The use of EGM2008 model improves the 3D coordinates accuracy to the level of precise GNSS measurements, while lack of this data introduce spatial displacements of the measured points, up to 26 cm. Hence our method can be useful for building precise 3D models of terrestrial objects in the GRS80 geocentric coordinate system. Numéro de notice : A2017-546 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1080/00396265.2016.1151969 En ligne : https://doi.org/10.1080/00396265.2016.1151969 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86601 [article]