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The development and performance of the VeraPhase antenna / Julien Hautcoeur in GPS world, vol 27 n° 7 (July 2016)
[article]
Titre : The development and performance of the VeraPhase antenna Type de document : Article/Communication Auteurs : Julien Hautcoeur, Auteur ; Ronald Johnston, Auteur ; Panther Gyles, Auteur Année de publication : 2016 Article en page(s) : pp 42 - 48 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] antenne GNSS
[Termes IGN] fréquence multiple
[Termes IGN] performanceRésumé : (éditeur) In this month's column, we take a look at a revolutionary design of a multi-frequency multi-GNSS antenna. Our authors discuss how the antenna evolved from a research project in academic to commercial product about to enter the market. Numéro de notice : A2016-529 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81603
in GPS world > vol 27 n° 7 (July 2016) . - pp 42 - 48[article]Performance analysis of triple-frequency ambiguity resolution with BeiDou observations / Xiaohong Zhang in GPS solutions, vol 20 n° 2 (April 2016)
[article]
Titre : Performance analysis of triple-frequency ambiguity resolution with BeiDou observations Type de document : Article/Communication Auteurs : Xiaohong Zhang, Auteur ; Xiyang He, Auteur Année de publication : 2016 Article en page(s) : pp 269 - 281 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] compensation Lambda
[Termes IGN] correction du trajet multiple
[Termes IGN] données BeiDou
[Termes IGN] performance
[Termes IGN] récepteur trifréquence
[Termes IGN] résolution d'ambiguïtéRésumé : (Auteur) We investigate triple-frequency ambiguity resolution performance using real BeiDou data. We test four ambiguity resolution (AR) methods which are applicable to triple-frequency observations. These are least squares ambiguity decorrelation adjustment (LAMBDA), GF-TCAR (geometry-free three-carrier ambiguity resolution), GB-TCAR (geometry-based three-carrier ambiguity resolution) and GIF-TCAR (three-carrier ambiguity resolution based on the geometry-free and ionospheric-free combination). A comparison between LAMBDA, GF-TCAR and GB-TCAR was conducted over three short baselines and two medium baselines. The results indicated that LAMBDA is optimal in both short baseline and medium baseline cases. However, the performances of GB-TCAR and LAMBDA differ slightly for short baselines. Compared with GF-TCAR, which uses the geometry-free model, the GB-TCAR using the geometry-based model improves the AR performance significantly. Compared with dual-frequency observations, the LAMBDA AR results show a significant improvement when using triple-frequency observations over short baselines. The performance of GIF-TCAR is evaluated using multi-epoch observations. The results indicated that multi-path errors on carrier phases will have a significant influence on GIF-TCAR AR results, which leads to different GIF-TCAR AR performance for different type of satellites. For GEO (Geostationary Orbit) satellites, the ambiguities can barely be correctly fixed because the multi-path errors on carrier phases are very systematic. For IGSO (Inclined Geosynchronous Orbit) and MEO (Medium Earth Orbit) satellites, when the elevation cutoff angle is set as 30°, several tens to several hundreds of epochs are needed for correctly fixing the narrow lane ambiguities. The comparison of positioning performance between dual-frequency observations and triple-frequency observations was also conducted. The results indicated that a minor improvement can be achieved by using triple-frequency observations compared with using dual-frequency observations. Numéro de notice : A2016-614 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-014-0434-0 En ligne : http://dx.doi.org/10.1007/s10291-014-0434-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81814
in GPS solutions > vol 20 n° 2 (April 2016) . - pp 269 - 281[article]A framework towards a composite indicator for urban ecosystem services / Mahbubul Alam in Ecological indicators, vol 60 (January 2016)
[article]
Titre : A framework towards a composite indicator for urban ecosystem services Type de document : Article/Communication Auteurs : Mahbubul Alam, Auteur ; Jérôme Dupras, Auteur ; Christian Messier, Auteur Année de publication : 2016 Article en page(s) : pp 38 - 44 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Environnement
[Termes IGN] forêt urbaine
[Termes IGN] indicateur de service écosystémique
[Termes IGN] performance
[Termes IGN] service écosystémiqueRésumé : (auteur) This article describes a composite indicator for ecosystem services. This composite is composed of several sub-indices, each representing either land use types or ecosystem services. While the overall composite indicates a general overview of the performance of a system in terms of ecosystem services provision, the sub-indices provide sources of variation. Taking into consideration potential trade-offs between making the framework complex and keeping it simple, the composite was developed on two levels. The first level, a simpler one, requires few indicators and therefore needs less data as inputs. The second level, in contrast, is more complex requiring more indicators, involving more detailed measurements, and therefore can be applied with more confidence. Numéro de notice : A2016-336 Affiliation des auteurs : non IGN Thématique : BIODIVERSITE/FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.ecolind.2015.05.035 En ligne : http://dx.doi.org/10.1016/j.ecolind.2015.05.035 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81018
in Ecological indicators > vol 60 (January 2016) . - pp 38 - 44[article]Légitimisation et suivi de la performance / Laurent Polidori in Géomètre, n° 2129 (octobre 2015)
[article]
Titre : Légitimisation et suivi de la performance Type de document : Article/Communication Auteurs : Laurent Polidori, Auteur Année de publication : 2015 Article en page(s) : pp 30 - 34 Langues : Français (fre) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] équipement sportif
[Termes IGN] géopositionnement
[Termes IGN] instrument de mesure
[Termes IGN] performance
[Termes IGN] positionnement en intérieur
[Termes IGN] précision des mesures
[Termes IGN] précision du positionnement
[Termes IGN] surveillance d'ouvrageRésumé : (auteur) Quand une performance sportive se calcule au centième de seconde, inutile d'insister sur l'importance de l’extrême précision des équipements de compétition et du contrôle des résultats. Domaine d'excellence des géomètres-experts. Numéro de notice : A2015-648 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78154
in Géomètre > n° 2129 (octobre 2015) . - pp 30 - 34[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 063-2015091 RAB Revue Centre de documentation En réserve L003 Disponible Querying visible points in large obstructed space / Jianqiu Xu in Geoinformatica, vol 19 n° 3 (July - September 2015)
[article]
Titre : Querying visible points in large obstructed space Type de document : Article/Communication Auteurs : Jianqiu Xu, Auteur ; Ralf Hartmut Güting, Auteur Année de publication : 2015 Article en page(s) : pp 435 - 461 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées
[Termes IGN] base de données localisées
[Termes IGN] géomètrie algorithmique
[Termes IGN] noeud
[Termes IGN] performance
[Termes IGN] point d'intérêt
[Termes IGN] structure de données localisées
[Termes IGN] traitement automatique de données
[Termes IGN] traitement de données localisées
[Termes IGN] triangulation (topologie)Résumé : (auteur) Querying visible points is a fundamental problem in computational geometry and spatial databases. With the development of new applications such as trip planning and nearest neighbors, querying visible points plays a key role in obstacle space and the result can be further used such as defining the shortest path. Thereby, efficiently finding the result is essentially important. However, the performance of current methods decrease substantially for large datasets. To solve the problem, we proposes a new and fast algorithm to find visible points for an arbitrary query location inside a large polygon containing obstacles. The method is based on polygon triangulation. By decomposing the polygon into a set of triangles, we manage the polygon by organizing triangles in an efficient way instead of maintaining a large number of vertices. We propose a data structure to partition the searching space into several parts, each of which is independently processed. Afterwards, by recursively calling a method we search visible points by accessing triangles and return the result in a progressive way. Through a theoretical analysis, assuming the polygon contains N vertices in total, the time complexity of our algorithm is O(N), improving the existing method O(N l o g N). We prove the correctness of the algorithm and analyze the space complexity, which is O(N). The technique is extended to return visible points less than a threshold distance to the query location. Using both synthetic and real datasets, we perform extensive experiments to test our algorithm and demonstrate its efficiency and effectiveness. Visible points are efficiently processed in a large obstacle space with over one million vertices. Experimental results show that our technique gains more than one order of magnitude speedup compared to competitive methods using large datasets. Numéro de notice : A2015-495 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1007/s10707-014-0213-7 Date de publication en ligne : 15/08/2014 En ligne : https://doi.org/10.1007/s10707-014-0213-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77307
in Geoinformatica > vol 19 n° 3 (July - September 2015) . - pp 435 - 461[article]Recommendations in location-based social networks: a survey / Jie Bao in Geoinformatica, vol 19 n° 3 (July - September 2015)PermalinkSpectral–spatial classification for hyperspectral data using rotation forests with local feature extraction and markov random fields / Junshi Xia in IEEE Transactions on geoscience and remote sensing, vol 53 n° 5 (mai 2015)PermalinkGalileo E1 and E5a Performance for multi-frequency, multi-constellation GBAS / Mihaela-Simona Circiu in GPS world, vol 26 n° 4 (April 2015)PermalinkPerformance analysis of radial basis function networks and multi-layer perceptron networks in modeling urban change: a case study / Hossein Shafizadeh-Moghadam in International journal of geographical information science IJGIS, vol 29 n° 4 (April 2015)PermalinkPermalinkESA's Soil Moisture and Ocean Salinity mission : mission performance and operations / S. Mecklenburg in IEEE Transactions on geoscience and remote sensing, vol 50 n° 5 Tome 1 (May 2012)PermalinkRadiometric performance of the SMOS reference radiometers-assessment after one year of operation / J. Kainulainen in IEEE Transactions on geoscience and remote sensing, vol 50 n° 5 Tome 1 (May 2012)PermalinkAn efficient point cloud management method based on a 3D R-tree / J. Gong in Photogrammetric Engineering & Remote Sensing, PERS, vol 78 n° 4 (April 2012)PermalinkPermalinkEmpirical comparison of full-waveform Lidar algorithms: range extraction and discrimination performance / C. Parrish in Photogrammetric Engineering & Remote Sensing, PERS, vol 77 n° 8 (August 2011)Permalink