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The influence of artificial illumination of invar levelling rods / Štefan Rákay in Geodetski vestnik, vol 62 n° 4 (December 2018 - February 2019)
[article]
Titre : The influence of artificial illumination of invar levelling rods Type de document : Article/Communication Auteurs : Štefan Rákay, Auteur ; Slavomír Labant, Auteur ; Karol Bartoš, Auteur ; Katarína Pukanská, Auteur Année de publication : 2018 Article en page(s) : pp 619 - 629 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Nivellement
[Termes IGN] angle d'incidence
[Termes IGN] détecteur à transfert de charge
[Termes IGN] détection d'erreur
[Termes IGN] éclairement lumineux
[Termes IGN] erreur en altitude
[Termes IGN] erreur systématique
[Termes IGN] mire de nivellement
[Termes IGN] niveau numérique
[Termes IGN] stadia InvarRésumé : (auteur) Since the digital levels operate on the principle of image processing of the bar code of levelling rod, recorded by a CCD sensor, the proper lighting (i.e. illumination of the bar code) is important to achieve accurate results. The prevention of inappropriate lighting conditions is important for the correct recording of the image of bar code section. This paper examines the systematic error as a function of the angle of incidence at which an bar code is illuminated by artificial lighting in low light conditions. Further, the procedure of measurements and the analysis of results for the identification of such errors is proposed. The results of experimental measurements highlight the inappropriateness of bar code illumination at an angle of incidence of more than about 45 °. From the practical measurements, it was found that the angle of incidence 55 ° corresponds to an error of about 0.02 mm, which is twice as much as the resolution of the height measurement determined by the manufacturer. Numéro de notice : A2019-015 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.15292/geodetski-vestnik.2018.04.619-629 Date de publication en ligne : 30/11/2018 En ligne : https://doi.org/10.15292/geodetski-vestnik.2018.04.619-629 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91624
in Geodetski vestnik > vol 62 n° 4 (December 2018 - February 2019) . - pp 619 - 629[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 139-2018041 RAB Revue Centre de documentation En réserve L003 Disponible Towards operational marker-free registration of terrestrial lidar data in forests / Jean-François Tremblay in ISPRS Journal of photogrammetry and remote sensing, vol 146 (December 2018)
[article]
Titre : Towards operational marker-free registration of terrestrial lidar data in forests Type de document : Article/Communication Auteurs : Jean-François Tremblay, Auteur ; Martin Béland, Auteur Année de publication : 2018 Article en page(s) : pp 430 - 435 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] analyse comparative
[Termes IGN] canopée
[Termes IGN] cible réfléchissante
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] Etats-Unis
[Termes IGN] forêt
[Termes IGN] inventaire forestier (techniques et méthodes)
[Termes IGN] matrice de covariance
[Termes IGN] modèle numérique de terrain
[Termes IGN] Québec (Canada)
[Termes IGN] semis de pointsRésumé : (auteur) Terrestrial laser scanning (TLS) often makes use of multiple scans in forests to allow for a complete view of a given area. Combining measurements from multiple locations requires accurate co-registration of the scans to a common reference coordinate system, which currently relies on markers, an often cumbersome process in forests. Existing algorithms for achieving marker-free registration of TLS scans in forests promise to significantly decrease field work time, but are not yet operational and their results have not been validated against traditional methods. Here we present a new implementation of an existing approach which runs in parallel mode and is able to process TLS data acquired over large forest areas. To validate our algorithm, point cloud registration matrices (translation and rotation) derived from our algorithm were compared to those obtained using reflective markers in multiple forest types. The results show that our approach can be used operationally in forests with relatively clear understory, and it provides accuracy similar to that obtained from using reflective markers. Furthermore, we identified factors that can lead to this approach falling short of providing acceptable results in terms of accuracy. Numéro de notice : A2018-542 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2018.10.011 Date de publication en ligne : 02/11/2018 En ligne : https://doi.org/10.1016/j.isprsjprs.2018.10.011 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91566
in ISPRS Journal of photogrammetry and remote sensing > vol 146 (December 2018) . - pp 430 - 435[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 081-2018131 RAB Revue Centre de documentation En réserve L003 Disponible 081-2018133 DEP-EXM Revue LASTIG Dépôt en unité Exclu du prêt 081-2018132 DEP-EAF Revue Nancy Dépôt en unité Exclu du prêt Estimation of satellite position, clock and phase bias corrections / Patrick Henkel in Journal of geodesy, vol 92 n° 10 (October 2018)
[article]
Titre : Estimation of satellite position, clock and phase bias corrections Type de document : Article/Communication Auteurs : Patrick Henkel, Auteur ; Dimitrios Psychas, Auteur ; Christophe Günther, Auteur ; Urs Hugentobler, Auteur Année de publication : 2018 Article en page(s) : pp 1199 - 1217 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] ambiguïté entière
[Termes IGN] données Galileo
[Termes IGN] données GPS
[Termes IGN] double différence
[Termes IGN] erreur de phase
[Termes IGN] horloge atomique
[Termes IGN] positionnement ponctuel précis
[Termes IGN] station de référenceRésumé : (Auteur) Precise point positioning with integer ambiguity resolution requires precise knowledge of satellite position, clock and phase bias corrections. In this paper, a method for the estimation of these parameters with a global network of reference stations is presented. The method processes uncombined and undifferenced measurements of an arbitrary number of frequencies such that the obtained satellite position, clock and bias corrections can be used for any type of differenced and/or combined measurements. We perform a clustering of reference stations. The clustering enables a common satellite visibility within each cluster and an efficient fixing of the double difference ambiguities within each cluster. Additionally, the double difference ambiguities between the reference stations of different clusters are fixed. We use an integer decorrelation for ambiguity fixing in dense global networks. The performance of the proposed method is analysed with both simulated Galileo measurements on E1 and E5a and real GPS measurements of the IGS network. We defined 16 clusters and obtained satellite position, clock and phase bias corrections with a precision of better than 2 cm. Numéro de notice : A2018-461 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-018-1146-y Date de publication en ligne : 02/05/2018 En ligne : https://doi.org/10.1007/s00190-018-1146-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91060
in Journal of geodesy > vol 92 n° 10 (October 2018) . - pp 1199 - 1217[article]Evaluation of three ionospheric delay computation methods for ground-based GNSS receivers / Liang Chen in GPS solutions, vol 22 n° 4 (October 2018)
[article]
Titre : Evaluation of three ionospheric delay computation methods for ground-based GNSS receivers Type de document : Article/Communication Auteurs : Liang Chen, Auteur ; Wenting Yi, Auteur ; Weiwei Song, Auteur ; Chuang Shi, Auteur ; Yidong Lou, Auteur ; Cheng Cao, Auteur Année de publication : 2018 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] analyse comparative
[Termes IGN] erreur systématique inter-systèmes
[Termes IGN] positionnement ponctuel précis
[Termes IGN] récepteur GNSS
[Termes IGN] retard ionosphèrique
[Vedettes matières IGN] Traitement de données GNSSMots-clés libres : carrier-to-code leveling (CCL) method ionospheric-free Hatch–Melbourne–Wubbena (HMW) function Résumé : (Auteur) GNSS observables for ionospheric estimation are commonly based on carrier-to-code leveling (CCL) and precise point positioning (PPP) methods. The CCL method is a geometry-free method which uses carrier phase to level pseudorange observation for decreasing multipath error and observation noise. However, the ionospheric observable based on the CCL has been proven to be affected by leveling errors. The leveling errors are caused by pseudorange multipath and intraday variation of receiver DCB. To obtain more accurate ionospheric observable, the PPP method takes advantage of precise satellite-to-ground range for retrieving slant total electron content and is less affected by the leveling errors. Previous studies have only proven that the ionospheric observables extracted by the two methods are affected by the leveling errors. The influence on ionospheric observable by the pseudorange inter-receiver satellite bias (IRSB) of the receiver has not been taken into consideration. Also, the magnitude of the differences between the ionospheric observables extracted by the two methods has also not been given. In this work, three methods, namely, the CCL, the conventional ionospheric-free PPP method which uses the ionospheric-free Hatch–Melbourne–Wubbena (HMW) function, and the University of Calgary (UOFC) PPP method, are selected to analyze and compare the differences of ionospheric observables and the global ionospheric maps, using a large number of measured data from international GNSS service global stations. Experimental results show that the accuracy of ionospheric observables obtained by the three methods is not only related to the leveling error, but also pseudorange IRSB. The IRSB of the receiver exerts a major effect on the ionospheric observables obtained by the CCL method and a minor effect on the ionospheric observables obtained by the HMW and UOFC methods. The accuracies in the latter case are similar and superior to those obtained by the CCL. The differences of the ionospheric observables obtained by the CCL and UOFC methods, or the CCL and HMW methods, are at decimeter level, whereas the difference of the ionospheric observables obtained by the UOFC and HMW methods is at centimeter level. The UOFC method presented the highest single-frequency pseudorange positioning accuracy using estimated global ionospheric products, followed by the HMW and the CCL methods which presented the lowest positioning accuracy. Numéro de notice : A2018-376 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-018-0788-9 Date de publication en ligne : 01/10/2018 En ligne : https://doi.org/10.1007/s10291-018-0788-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90780
in GPS solutions > vol 22 n° 4 (October 2018)[article]GPS satellite clock determination in case of inter-frequency clock biases for triple-frequency precise point positioning / Jiang Guo in Journal of geodesy, vol 92 n° 10 (October 2018)
[article]
Titre : GPS satellite clock determination in case of inter-frequency clock biases for triple-frequency precise point positioning Type de document : Article/Communication Auteurs : Jiang Guo, Auteur ; Jianghui Geng, Auteur Année de publication : 2018 Article en page(s) : pp 1133 - 1142 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] erreur systématique
[Termes IGN] horloge atomique
[Termes IGN] positionnement ponctuel précis
[Termes IGN] satellite GPSRésumé : (Auteur) Significant time-varying inter-frequency clock biases (IFCBs) within GPS observations prevent the application of the legacy L1/L2 ionosphere-free clock products on L5 signals. Conventional approaches overcoming this problem are to estimate L1/L5 ionosphere-free clocks in addition to their L1/L2 counterparts or to compute IFCBs between the L1/L2 and L1/L5 clocks which are later modeled through a harmonic analysis. In contrast, we start from the undifferenced uncombined GNSS model and propose an alternative approach where a second satellite clock parameter dedicated to the L5 signals is estimated along with the legacy L1/L2 clock. In this manner, we do not need to rely on the correlated L1/L2 and L1/L5 ionosphere-free observables which complicates triple-frequency GPS stochastic models, or account for the unfavorable time-varying hardware biases in undifferenced GPS functional models since they can be absorbed by the L5 clocks. An extra advantage over the ionosphere-free model is that external ionosphere constraints can potentially be introduced to improve PPP. With 27 days of triple-frequency GPS data from globally distributed stations, we find that the RMS of the positioning differences between our GPS model and all conventional models is below 1 mm for all east, north and up components, demonstrating the effectiveness of our model in addressing triple-frequency observations and time-varying IFCBs. Moreover, we can combine the L1/L2 and L5 clocks derived from our model to calculate precisely the L1/L5 clocks which in practice only depart from their legacy counterparts by less than 0.006 ns in RMS. Our triple-frequency GPS model proves convenient and efficient in combating time-varying IFCBs and can be generalized to more than three frequency signals for satellite clock determination. Numéro de notice : A2018-460 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-017-1106-y Date de publication en ligne : 28/12/2017 En ligne : https://doi.org/10.1007/s00190-017-1106-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91057
in Journal of geodesy > vol 92 n° 10 (October 2018) . - pp 1133 - 1142[article]Methods for quantification of systematic distance deviations under incidence angle with scanning total stations / Miriam Zámečníková in ISPRS Journal of photogrammetry and remote sensing, vol 144 (October 2018)PermalinkPPPH : a MATLAB-based software for multi-GNSS precise point positioning analysis / Berkay Bahadur in GPS solutions, vol 22 n° 4 (October 2018)PermalinkLa cartographie mobile et le géoréférencement précis de réseaux souterrains / Garance Weller in XYZ, n° 156 (septembre - novembre 2018)PermalinkGNSS-assisted integrated sensor orientation with sensor pre-calibration for accurate corridor mapping / Yilin Zhou in Sensors, vol 18 n° 9 (September 2018)PermalinkIn-situ measurements from mobile platforms: An emerging approach to address the old challenges associated with forest inventories / Xinlian Liang in ISPRS Journal of photogrammetry and remote sensing, vol 143 (September 2018)PermalinkA quelles altitudes se trouvent les horloges atomiques de l'observatoire de Paris ? / Xavier Collilieux in XYZ, n° 156 (septembre - novembre 2018)PermalinkA deep learning approach to DTM extraction from imagery using rule-based training labels / Caroline M. Gevaert in ISPRS Journal of photogrammetry and remote sensing, vol 142 (August 2018)PermalinkDetecting newly grown tree leaves from unmanned-aerial-vehicle images using hyperspectral target detection techniques / Chinsu Lin in ISPRS Journal of photogrammetry and remote sensing, vol 142 (August 2018)PermalinkThe use of geomatic techniques to improve the management of metro infrastructure / Maria Amparo Núñez-Andrés in Survey review, vol 50 n° 362 (August 2018)PermalinkAerial data acquisition for a digital railway / James Dunthorne in GIM international, vol 32 n° 4 (July - August 2018)PermalinkComparative analysis of multi-constellation GNSS single-frequency precise point positioning / Mahmoud Abd Rabbou in Survey review, vol 50 n° 361 (July 2018)PermalinkDrones et SIG / Anonyme in Géomatique expert, n° 122 (mai-juin 2018)PermalinkExtracting leaf area index using viewing geometry effects : A new perspective on high-resolution unmanned aerial system photography / Lukas Roth in ISPRS Journal of photogrammetry and remote sensing, vol 141 (July 2018)PermalinkA fully automatic approach to register mobile mapping and airborne imagery to support the correction of plateform trajectories in GNSS-denied urban areas / Phillipp Jende in ISPRS Journal of photogrammetry and remote sensing, vol 141 (July 2018)PermalinkOdometer, low-cost inertial sensors, and four-GNSS data to enhance PPP and attitude determination / Zhouzheng Gao in GPS solutions, vol 22 n° 3 (July 2018)PermalinkAdvancement of close range photogrammetry with a portable panoramic image mapping system (PPIMS) / Yung-Chuan Chen in Photogrammetric record, vol 33 n° 162 (June 2018)PermalinkCartographie pour la réflexion sur un périmètre à irriguer dans le Sud Kivu / Anne Girardin in XYZ, n° 155 (juin - août 2018)PermalinkData collection methods for forest inventory: a comparison between an integrated conventional equipment and terrestrial laser scanning / Bogdan Apostol in Annals of forest research, vol 61 n° 2 (July - December 2018)PermalinkFinding timestamp offsets for a multi-sensor system using sensor observations / Raphael Voges in Photogrammetric Engineering & Remote Sensing, PERS, vol 84 n° 6 (juin 2018)PermalinkGeometric model and assessment of a dual‐fisheye imaging system / Mariana Batista Campos in Photogrammetric record, vol 33 n° 162 (June 2018)Permalink