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A remark on the GNSS single difference model with common clock scheme for attitude determination / Wantong Chen in Journal of applied geodesy, vol 10 n° 3 (September 2016)
[article]
Titre : A remark on the GNSS single difference model with common clock scheme for attitude determination Type de document : Article/Communication Auteurs : Wantong Chen, Auteur Année de publication : 2016 Article en page(s) : pp 167 – 173 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] antenne GNSS
[Termes IGN] erreur de phase
[Termes IGN] erreur systématique
[Termes IGN] horloge
[Termes IGN] orientation du capteur
[Termes IGN] phase GNSS
[Termes IGN] simple différenceRésumé : (auteur) GNSS-based attitude determination technique is an important field of study, in which two schemes can be used to construct the actual system: the common clock scheme and the non-common clock scheme. Compared with the non-common clock scheme, the common clock scheme can strongly improve both the reliability and the accuracy. However, in order to gain these advantages, specific care must be taken in the implementation. The cares are thus discussed, based on the generating technique of carrier phase measurement in GNSS receivers. A qualitative assessment of potential phase bias contributes is also carried out. Possible technical difficulties are pointed out for the development of single-board multi-antenna GNSS attitude systems with a common clock. Numéro de notice : A2016-970 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jag-2016-0008 En ligne : https://doi.org/10.1515/jag-2016-0008 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83677
in Journal of applied geodesy > vol 10 n° 3 (September 2016) . - pp 167 – 173[article]Understanding the bias of call detail records in human mobility research / Ziliang Zhao in International journal of geographical information science IJGIS, vol 30 n° 9-10 (September - October 2016)
[article]
Titre : Understanding the bias of call detail records in human mobility research Type de document : Article/Communication Auteurs : Ziliang Zhao, Auteur ; Shih-Lung Shaw, Auteur ; Yang Xu, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 1738 - 1762 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale
[Termes IGN] Chine
[Termes IGN] contenu généré par les utilisateurs
[Termes IGN] données massives
[Termes IGN] erreur systématique
[Termes IGN] mobilité humaine
[Termes IGN] navigation pédestre
[Termes IGN] statistiques d'appels détaillés
[Termes IGN] téléphonie mobileRésumé : (Auteur) In recent years, call detail records (CDRs) have been widely used in human mobility research. Although CDRs are originally collected for billing purposes, the vast amount of digital footprints generated by calling and texting activities provide useful insights into population movement. However, can we fully trust CDRs given the uneven distribution of people’s phone communication activities in space and time? In this article, we investigate this issue using a mobile phone location dataset collected from over one million subscribers in Shanghai, China. It includes CDRs (~27%) plus other cellphone-related logs (e.g., tower pings, cellular handovers) generated in a workday. We extract all CDRs into a separate dataset in order to compare human mobility patterns derived from CDRs vs. from the complete dataset. From an individual perspective, the effectiveness of CDRs in estimating three frequently used mobility indicators is evaluated. We find that CDRs tend to underestimate the total travel distance and the movement entropy, while they can provide a good estimate to the radius of gyration. In addition, we observe that the level of deviation is related to the ratio of CDRs in an individual’s trajectory. From a collective perspective, we compare the outcomes of these two datasets in terms of the distance decay effect and urban community detection. The major differences are closely related to the habit of mobile phone usage in space and time. We believe that the event-triggered nature of CDRs does introduce a certain degree of bias in human mobility research and we suggest that researchers use caution to interpret results derived from CDR data. Numéro de notice : A2016-567 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/SOCIETE NUMERIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/13658816.2015.1137298 En ligne : http://dx.doi.org/10.1080/13658816.2015.1137298 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81710
in International journal of geographical information science IJGIS > vol 30 n° 9-10 (September - October 2016) . - pp 1738 - 1762[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 079-2016051 RAB Revue Centre de documentation En réserve L003 Disponible A geometry-free and ionosphere-free multipath mitigation method for BDS three-frequency ambiguity resolution / Dezhong Chen in Journal of geodesy, vol 90 n° 8 (August 2016)
[article]
Titre : A geometry-free and ionosphere-free multipath mitigation method for BDS three-frequency ambiguity resolution Type de document : Article/Communication Auteurs : Dezhong Chen, Auteur ; Shirong Ye, Auteur ; Jingchao Xia, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 703 – 714 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] correction du trajet multiple
[Termes IGN] erreur systématique
[Termes IGN] positionnement par BeiDou
[Termes IGN] résolution d'ambiguïté
[Termes IGN] signal BeiDou
[Termes IGN] station de référence
[Termes IGN] trajet multiple
[Termes IGN] troposphèreRésumé : (auteur) Because of the unknown systematic errors and special satellite constellations in the Beidou system (BDS), it is difficult to quickly and reliably determine the ambiguity over long-range baselines in continuously operating reference station (CORS) network. This study seeks to improve the effectiveness and reliability of BDS ambiguity resolution (AR) by combining the geometry-free and ionosphere-free (GFIF) combination and multipath mitigation algorithm. The GFIF combination composed with three-frequency signals is free of distance-dependent errors and can be used to determine the narrow lane ambiguity. The presence of multipath errors means that not all ambiguities can be correctly achieved by rounding the averaged GFIF ambiguity series. A multipath model of the single-differenced (SD) GFIF combination from the previous period is established for each individual satellite. This model is subtracted from the SD GFIF combination for the current day to remove the effects of multipath errors. Using three triangle networks with lengths of approximately 120, 80 and 50 km, we demonstrate that the proposed method improves the AR performance. The ambiguity averaged first fixing time is typically less than 1801 s for inclined geosynchronous orbit (IGSO) and medium earth orbit (MEO) satellites and less than 2007 s for the ∼42∘ elevation geostationary earth orbit (GEO) C02 satellite. However, it is more time consuming for the low-elevation GEO satellites C04 (∼18∘) and C05 (∼28∘). Kalman filtering is used to estimate the troposphere delays and two unfixed ambiguities by employing the ionosphere-free observations of all ambiguity-fixed/unfixed satellites. The experimental results show that only tens of seconds are required for AR in around 90 km baselines. Numéro de notice : A2016-503 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-016-0903-z En ligne : http://dx.doi.org/10.1007/s00190-016-0903-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81527
in Journal of geodesy > vol 90 n° 8 (August 2016) . - pp 703 – 714[article]The study of key issues about integration of GNSS and strong-motion records for real-time earthquake monitoring / Rui Tu in Advances in space research, vol 58 n° 3 (August 2016)
[article]
Titre : The study of key issues about integration of GNSS and strong-motion records for real-time earthquake monitoring Type de document : Article/Communication Auteurs : Rui Tu, Auteur ; Pengfei Zhang, Auteur ; Rui Zhang, Auteur ; Jinhai Liu, Auteur Année de publication : 2016 Article en page(s) : pp 304 - 309 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] coordonnées GPS
[Termes IGN] erreur systématique
[Termes IGN] intégration de données
[Termes IGN] qualité des données
[Termes IGN] surveillance géologique
[Termes IGN] temps réelRésumé : (auteur) This paper has studied the key issues about integration of GNSS and strong-motion records for real-time earthquake monitoring. The validations show that the consistence of the coordinate system must be considered firstly to exclude the system bias between GNSS and strong-motion. The GNSS sampling rate is suggested about 1–5 Hz, and we should give the strong-motion’s baseline shift with a larger dynamic noise as its variation is very swift. The initialization time of solving the baseline shift is less than one minute, and ambiguity resolution strategy is not greatly improved the solution. The data quality is very important for the solution, we advised to use multi-frequency and multi-system observations. These ideas give an important guide for real-time earthquake monitoring and early warning by the tight integration of GNSS and strong-motion records. Numéro de notice : A2016-589 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2016.04.033 En ligne : http://dx.doi.org/10.1016/j.asr.2016.04.033 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81744
in Advances in space research > vol 58 n° 3 (August 2016) . - pp 304 - 309[article]Multisensor and multispectral Lidar characterization and classification of a forest environment / Christopher Hopkinson in Canadian journal of remote sensing, vol 42 n° 5 ([01/05/2016])
[article]
Titre : Multisensor and multispectral Lidar characterization and classification of a forest environment Type de document : Article/Communication Auteurs : Christopher Hopkinson, Auteur ; Laura Chasmer, Auteur ; Chris Gynan, Auteur ; Craig Mahoney, Auteur ; Michael Sitar, Auteur Année de publication : 2016 Article en page(s) : pp 501 - 520 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] canopée
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] erreur systématique
[Termes IGN] feuille (végétation)
[Termes IGN] modèle numérique de surface
[Termes IGN] modèle numérique de surface de la canopée
[Termes IGN] rayonnement proche infrarougeRésumé : (auteur) Airborne LiDAR is increasingly used in forest carbon, ecosystem, and resource monitoring. For practical design and manufacture reasons, the 1064 nm near-infrared (NIR) wavelength has been the most commonly adopted, and most literature in this field represents sampling characteristics in this wavelength. However, due to eye-safety and application-specific needs, other common wavelengths are 1550 nm and 532 nm. All provide canopy structure reconstructions that can be integrated or compared through space and time but the consistency or complementarity of 3D airborne LiDAR data sampled at multiple wavelengths is poorly understood. Here, we report on multispectral LiDAR missions carried out in 2013 and 2015 over a managed forest research site. The 1st used 3 independent sensors, and the 2nd used a single sensor carrying 3 lasers. The experiment revealed differences in proportions of returns at ground level, vertical foliage distributions, and gap probability across wavelengths. Canopy attenuation was greatest at 532 nm, presumably due to leaf tissue absorption. Relative to 1064 nm, foliage was undersampled at midheight percentiles at 1550 nm and 532 nm. Multisensor data demonstrated differences in foliage characterization due to combined influences of wavelength and acquisition configuration. Single-sensor multispectral data were more stable but demonstrated clear wavelength-dependent variation that could be exploited in intensity-based land cover classification without the aid of 3D derivatives. This work sets the stage for improvements in land surface classification and vertical foliage partitioning through the integration of active spectral and structural laser return information. Numéro de notice : A2016--128 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.1080/07038992.2016.1196584 En ligne : http://dx.doi.org/10.1080/07038992.2016.1196584 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85114
in Canadian journal of remote sensing > vol 42 n° 5 [01/05/2016] . - pp 501 - 520[article]Comparative analysis of real-time precise point positioning zenith total delay estimates / F.A. Ahmed in GPS solutions, vol 20 n° 2 (April 2016)PermalinkA study on the dependency of GNSS pseudorange biases on correlator spacing / André Hauschild in GPS solutions, vol 20 n° 2 (April 2016)PermalinkChallenges and present fields of action at laser scanner based deformation analyses / Christoph Holst in Journal of applied geodesy, vol 10 n° 1 (March 2016)PermalinkDetermination of differential code biases with multi-GNSS observations / Ningbo Wang in Journal of geodesy, vol 90 n° 3 (March 2016)PermalinkNoise simulation and correction in synthetic airborne TIR Data for mineral quantification / Christoph Hecker in IEEE Transactions on geoscience and remote sensing, vol 54 n° 3 (March 2016)PermalinkPermalinkError analysis of a new planar electrostatic gravity gradiometer for airborne surveys / Karim Douch in Journal of geodesy, vol 89 n° 12 (december 2015)PermalinkMulti-GNSS as a combination of GPS, GLONASS and Beidou measurements carried out in real time / Zbigniew Siejka in Artificial satellites, vol 50 n° 4 (December 2015)PermalinkParticle filter-based estimation of inter-frequency phase bias for real-time GLONASS integer ambiguity resolution / Yumiao Tian in Journal of geodesy, vol 89 n° 11 (november 2015)PermalinkAnalysis of different methods for 3D reconstruction of natural surfaces from parallel-axes UAV images / Annette Eltner in Photogrammetric record, vol 30 n° 151 (September - November 2015)Permalink