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Opening up new opportunities in high-precision GNSS / Chuck Joseph in GIM international, vol 30 n° 3 (March 2016)
[article]
Titre : Opening up new opportunities in high-precision GNSS Type de document : Article/Communication Auteurs : Chuck Joseph, Auteur Année de publication : 2016 Article en page(s) : pp 12 - 15 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] entreprise
[Termes IGN] instrumentation GNSS
[Termes IGN] positionnement par GNSSRésumé : (éditeur) In a fiercely compétitive landscape, there is considerable pressure on GNSS companies such as Hemisphere GNSS to be innovative and respond to the challenging market conditions. New developments, such as the expansion of the Chinese BeiDou and the European Galileo systems as well as the spectacular rise of Mis, demand a long-term strategy combined with the agility to adapt. Chuck Joseph, president and CEO of Hemisphere GNSS (HGNSS), explains how his company strives to play a leadership role in the industry. Numéro de notice : A2016-101 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79924
in GIM international > vol 30 n° 3 (March 2016) . - pp 12 - 15[article]Opportunity for accuracy: Exploiting terrestrial signals of opportunity / Joshua J. Morales in GPS world, vol 27 n° 3 (March 2016)
[article]
Titre : Opportunity for accuracy: Exploiting terrestrial signals of opportunity Type de document : Article/Communication Auteurs : Joshua J. Morales, Auteur ; Joe J. Khalife, Auteur ; Zaher M. Kassas, Auteur Année de publication : 2016 Article en page(s) : pp 22 - 29 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] affaiblissement de la précision
[Termes IGN] positionnement par GNSS
[Termes IGN] propagation du signalRésumé : (éditeur) (SOPs) can significantly reduce the vertical dilution of precision (VDOP) of a GNSS navigation solution. Simulation and experimental results show that that adding cellular SOP observables is more effective in reducing VDOP than adding GNSS space vehicle (SV) observables. Numéro de notice : A2016-093 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79884
in GPS world > vol 27 n° 3 (March 2016) . - pp 22 - 29[article]Potential of GPS common clock single-differences for deformation monitoring / Steffen Schön in Journal of applied geodesy, vol 10 n° 1 (March 2016)
[article]
Titre : Potential of GPS common clock single-differences for deformation monitoring Type de document : Article/Communication Auteurs : Steffen Schön, Auteur ; Hue Kiem Pham, Auteur ; Tobias Kersten, Auteur ; Julia Leute, Auteur ; Andreas Bauch, Auteur Année de publication : 2016 Article en page(s) : pp 45 - 52 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] déformation géométrique
[Termes IGN] hauteur ellipsoïdale
[Termes IGN] horloge
[Termes IGN] positionnement cinématique
[Termes IGN] récepteur GNSS
[Termes IGN] simple différence
[Vedettes matières IGN] Traitement de données GNSSRésumé : (auteur) Global satellite navigation systems (GNSS) are a standard measurement device for deformation monitoring. In many applications, double-differences are used to reduce distance dependent systematic effects, as well as to eliminate the receiver and satellites clock errors. However, due to the navigation principle of one way ranging used in GPS, the geometry of the subsequent adjustment is weakened. As a result, the height component is generally determined three times less precisely than the horizontal coordinates. In addition, large correlations between the height and elevation dependent effects exist such as tropospheric refraction, mismodelled phase center variations, or multipath which restricts the attainable accuracy. However, for a kinematic analysis, i. e. for estimating high rate coordinate time series, the situation can be significantly improved if a common clock is connected to different GNSS receivers in a network or on a baseline. Consequently, between-station single-differences are sufficient to solve for the baseline coordinates. The positioning geometry is significantly improved which is reflected by a reduction of the standard deviation of kinematic heights by about a factor 3 underlining the benefits of this new approach. Real data from baselines at the Physikalisch-Technische Bundesanstalt campus at Braunschweig where receivers are connected over 290 m via an optical fiber link to a common clock was analysed. Numéro de notice : A2016-553 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jag-2015-0029 En ligne : http://dx.doi.org/10.1515/jag-2015-0029 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81700
in Journal of applied geodesy > vol 10 n° 1 (March 2016) . - pp 45 - 52[article]Real time monitoring ground motion using GPS with real time corrections / R. Tu in Survey review, vol 48 n° 347 (March 2016)
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Titre : Real time monitoring ground motion using GPS with real time corrections Type de document : Article/Communication Auteurs : R. Tu, Auteur ; L. Wang, Auteur ; Z. Liu, Auteur Année de publication : 2016 Article en page(s) : pp 79 – 85 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] modèle d'erreur
[Termes IGN] mouvement de terrain
[Termes IGN] positionnement par GPS
[Termes IGN] résidu
[Termes IGN] station GPS
[Termes IGN] surveillance géologique
[Termes IGN] vitesseRésumé : (auteur) The high rate GPS velocity determination technology which is based on the broadcast ephemeris and epoch differenced model can retrieve displacement of ground motion with the precision of a few centimetres to decimetres in real time. Moreover, the precision of the recovered displacement can be improved if the un-modelled errors such as broadcast ephemeris residuals, atmospheric residuals, multipath effects and high frequency noise are tackled more accurately. In this paper, we propose a method to improve the precision of the recovered displacement by appropriately making use of reference station corrections. For the reference stations, the coordinates are highly constrained to extract the error corrections that are to be broadcast via a communication link to the rover. After correcting the rover’s observations, some errors such as ephemeris residuals and atmospheric residuals are effectively eliminated or at least reduced. This improves the accuracy of the observations and thus enhances the reliability of the velocity estimation. The displacement can be recovered by integrating the estimated velocity after de-trending using a linear trend that is caused by the un-corrected residuals. The series of validation results in the experiment have shown that the displacement of the simulated motion can be real time recovered with a precision of 1–2 cm, and is thus applicable for real time monitoring of the ground motion. Numéro de notice : A2016-047 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1179/1752270614Y.0000000141 En ligne : https://doi.org/10.1179/1752270614Y.0000000141 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79641
in Survey review > vol 48 n° 347 (March 2016) . - pp 79 – 85[article]Spatial accuracy of UAV- derived orthoimagery and topography: Comparing photogrammetric models processed with direct geo-referencing and ground control points / Chris H. Hugenholtz in Geomatica, vol 70 n° 1 (March 2016)
[article]
Titre : Spatial accuracy of UAV- derived orthoimagery and topography: Comparing photogrammetric models processed with direct geo-referencing and ground control points Type de document : Article/Communication Auteurs : Chris H. Hugenholtz, Auteur ; Owen Brown, Auteur ; Jordan Walker, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 21 - 30 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques
[Termes IGN] acquisition de données
[Termes IGN] analyse comparative
[Termes IGN] capteur aérien
[Termes IGN] drone
[Termes IGN] géoréférencement direct
[Termes IGN] point d'appui
[Termes IGN] positionnement cinématique en temps réel
[Termes IGN] positionnement inertiel
[Termes IGN] positionnement par GNSS
[Termes IGN] positionnement par GPS
[Termes IGN] qualité des données
[Termes IGN] réalité de terrain
[Termes IGN] topographieRésumé : (auteur) Mapping with unmanned aerial vehicles (UAVs) typically involves the deployment of ground control points (GCPs) to georeference the images and topographic model. An alternative approach is direct georeferencing, whereby the onboard Global Navigation Satellite System (GNSS) and inertial measurement unit are used without GCPs to locate and orient the data. This study compares the spatial accuracy of these approaches using two nearly identical UAVs. The onboard GNSS is the one difference between them, as one vehicle uses a survey-grade GNSS/RTK receiver (RTK UAV), while the other uses a lower-grade GPS receiver (non-RTK UAV). Field testing was performed at a gravel pit, with all ground measurements and aerial surveying completed on the same day. Three sets of orthoimages and DSMs were produced for comparing spatial accuracies: two sets were created by direct georeferencing images from the RTK UAV and non-RTK UAV and one set was created by using GCPs during the external orientation of the non-RTK UAV images. Spatial accuracy was determined from the horizontal (X,Y) and vertical (Z) residuals and root-mean-square-errors (RMSE) relative to 17 horizontal and 180 vertical check points measured with a GNSS/RTK base station and rover. For the two direct georeferencing datasets, the horizontal and vertical accuracy improved substantially with the survey-grade GNSS/RTK receiver onboard the RTK UAV, effectively reducing the RMSE values in X, Y and Z by 1 to 2 orders of magnitude compared to the lower grade GPS receiver onboard the non-RTK UAV. Importantly, the horizontal accuracy of the RTK UAV data processed via direct georeferencing was equivalent to the horizontal accuracy of the non-RTK UAV data processed with GCPs, but the vertical error of the DSM from the RTK UAV data was 2 to 3 times greater than the DSM from the non-RTK data with GCPs. Overall, results suggest that direct georeferencing with the RTK UAV can achieve horizontal accuracy comparable to that obtained with a network of GCPs, but for topographic measurements requiring the highest achievable accuracy, researchers and practitioners should use GCPs. Numéro de notice : A2016-433 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article DOI : 10.5623/cig2016-102 En ligne : https://doi.org/10.5623/cig2016-102 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81330
in Geomatica > vol 70 n° 1 (March 2016) . - pp 21 - 30[article]The Canadian Geodetic Vertical Datum of 2013 (CGVD2013) / Marc Véronneau in Geomatica, vol 70 n° 1 (March 2016)PermalinkAn enhanced algorithm to estimate BDS satellite’s differential code biases / Chuang Shi in Journal of geodesy, vol 90 n° 2 (February 2016)PermalinkIonospheric corrections for single-frequency tracking of GNSS satellites by VLBI based on co-located GNSS / Benjamin Männel in Journal of geodesy, vol 90 n° 2 (February 2016)PermalinkAdaptive GPS/INS integration for relative navigation / Je Young Lee in GPS solutions, vol 20 n° 1 (January 2016)PermalinkPermalinkPermalinkPermalinkEntwicklung einer direkten Georeferenzierungseinheit zur Positions- und Orientierungbestimmung leichter UAVs in Eichzeit / Christian Eling (2016)PermalinkGAGAN - India’s SBAS : Redefining Navigation over the Indian Region / A.S. Ganeshan in Inside GNSS, vol 11 n° 1 (January - February 2016)PermalinkGNSS Satellite-Based Augmentation Systems : A potential new time keeping system for future generations / Carlo Cornacchini in Inside GNSS, vol 11 n° 1 (January - February 2016)Permalink