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contenu dans AGILE 2003, 6th Agile Conference on Geographic Information Science, Lyon, 24 - 26 April, 2003 / Michael Gould (2003)
Titre : Wearable GIS : a smart assistant in disaster management Type de document : Article/Communication Auteurs : Joachim Baldegger, Auteur ; Christine Giger, Auteur Editeur : Zurich : Eidgenossische Technische Hochschule ETH - Ecole Polytechnique Fédérale de Zurich EPFZ Année de publication : 2003 Conférence : AGILE 2003, 6th international conference on geographic information science 24/04/2003 26/04/2003 Lyon France Open access proceedings Importance : pp 19 - 26 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes d'information géographique
[Termes IGN] appareil portable
[Termes IGN] catastrophe naturelle
[Termes IGN] positionnement par GPS
[Termes IGN] reconnaissance de la parole
[Termes IGN] requête spatiale
[Termes IGN] SIG nomadeRésumé : (Auteur) The use of GIS in a broad palette of applications has been practical and successful for several years. The enormous possibilities of these systems are appreciated and have been established as decision supporting tools in many processes. Today's GIS are usually static and often used in longterm planning and administering processes. The technological development in the IT and telecommunication sector shows a clear trend towards mobile applications. Such a mobile use would also be desirable in the GIST sector and would broaden the possible fields of application for those, who are in a need for quick decisions on the spot. Numéro de notice : C2003-008 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Communication DOI : sans En ligne : https://agile-online.org/conference_paper/cds/agile_2003/proceedings/2.pdf Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=64987
Titre : Zur Bestimmung der GPS-Phasenmehrdeutigkeiten in großräumigen Netzen Titre original : [Vers la résolution des ambiguïtés de phase GPS dans les réseaux à grande échelle] Type de document : Thèse/HDR Auteurs : K. Wienholz, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2003 Collection : DGK - C Sous-collection : Dissertationen num. 566 Importance : 102 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-5005-1 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] ambiguïté entière
[Termes IGN] ligne de base
[Termes IGN] logiciel de post-traitement GPS
[Termes IGN] mesurage de phase
[Termes IGN] modèle mathématique
[Termes IGN] phase GPS
[Termes IGN] propagation ionosphérique
[Termes IGN] résolution d'ambiguïté
[Termes IGN] traitement de données GNSSIndex. décimale : 30.61 Systèmes de Positionnement par Satellites du GNSS Résumé : (Auteur) The development and the results of the TUB method are presented in this paper. This special method serves in resolving GPS phase ambiguities in small-range and large-range networks. It is characterized by taking into account the correlates as quality criteria, thus enabling an assessment of the calculated ambiguities. First of all : by simulating an example to mediate the adjustment of conditions between unknown quantities it can be shown that every incorrect condition exerts a major constraint on the adjustment system. This constraint is reflected by the pertaining Lagrange factors (or correlates), the value of which increases rapidly in line with the magnitude of error in the equation of condition. This knowledge can be used in the TUB method to investigate various parameters. However, in this paper the emphasis is on the investigation of ambiguities.
The TUB method is based on a special parameterization of the observation equations so that several unknown parameters are combined in one newly established time-dependent auxiliary parameter and in one timeindependent auxiliary parameter. By reduction of the unknown parameters a stable equation system is brought about which can be solved without resulting in differences and linear combinations. The direct analysis of original phase observations prevents the error-propagation of accidental errors and hence an artificial increase in phase noise. Therefore the confidence intervals, characterized by integer numbers, can be kept rather small. In finding these integer numbers the time-dependent auxiliary parameters must first be separated in different ways, depending on the lengths of the base lines, from the ionospheric refraction. Then the ambiguities in the form of double differences, related to a base satellite and a base station (or in the form of L1/L2 ambiguity pairs), can be solved in an iterative process. As a controlling device equations of condition are formed with the help of L1/L2 ambiguity pairs and inserted in the adjustment process. A subsequent analysis of the correlates gives information about the qualities of the ambiguities found.
To begin with the potential of the TUB method is tested by means of a data set with base line lengths ranging from 13 to 48 km. By analyzing the correlates incorrect double difference ambiguities can be identified and among several integer numbers the correct one is filtered out. In two further nets with base line lengths from 26 to 106 km the influences of various more or less accurate orbits on the parameters of the observation equations are investigated. In the aforementioned examples a resolution of the ambiguities is possible at a success rate of 100 percent while an observation time of about two hours is sufficient. When terrain points are between 700 and 1000 km apart the model shows consider-able inaccuracies. The evaluation of data stemming from various IGS stations evidences that in about 20 percent of all ambiguities integer numbers cannot be found. In these cases the confidence intervals either do not provide any integer number or too many of them. In the latter case there are, instead of a single one, several LI/L2 ambiguity pairs that do not differ very much from one another. When these ambiguity pairs are inserted in the equation system the values of the correlates do not differ very much either. For the time being no satisfactory results can be achieved for base lines ranging between 1000 and 2000 km.
The analysis of the correlates proves to be a useful tool in evaluating the quality of ambiguities. The correlates with the highest values occur when incorrect ambiguities exert major constraints on the equations of condition. In these cases errors can be detected, e.g., those arising from the use of broad-cast ephemerides. When several integer numbers are found in the confidence intervals the values of the correlates suggest values matching the normal equation system. Considerable interdependencies of the equations of condition are evident. Consequently there is an increase in the values that are linked to an incorrect condition via satellite and station. Therefore the correlations between the Lagrange factors should be investigated more closely. It is useful to determine the ambiguities of a data set by observation times of different lengths. By comparing the double difference ambiguities calculated from these solutions an additional examination of the results is made possible. Particularly when base lines of more than 1000 km are used it turns out that with data resulting from shorter observation times integer numbers can be calculated that would either not result at all or only inaccurately from longer measurements. The use of correlates as indicators for incorrect conditions is not only suitable for evaluating ambiguities in GPS analysis. Moreover, all parameters that can be formulated in appropriate conditions may be examined in any case of problems regarding the analysis of data.Numéro de notice : 13191 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54906 Exemplaires(2)
Code-barres Cote Support Localisation Section Disponibilité 13191-02 30.61 Livre Centre de documentation Géodésie Disponible 13191-01 30.61 Livre Centre de documentation Géodésie Disponible The effect of broadleaf canopies on survey-grade horizontal GPS-GLONASS measurements / Thomas H. Meyer in Surveying and land information systems, vol 62 n° 4 (01/12/2002)
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Titre : The effect of broadleaf canopies on survey-grade horizontal GPS-GLONASS measurements Type de document : Article/Communication Auteurs : Thomas H. Meyer, Auteur ; J.E. Bean, Auteur ; C.R. Ferguson, Auteur ; J.M. Naismith, Auteur Année de publication : 2002 Article en page(s) : pp 215 - 224 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] diffusion du rayonnement
[Termes IGN] feuille (végétation)
[Termes IGN] instrumentation Trimble
[Termes IGN] ligne de base
[Termes IGN] positionnement par GLONASS
[Termes IGN] positionnement par GPS
[Termes IGN] récepteur GPS
[Termes IGN] récepteur mixte
[Termes IGN] seuillage
[Termes IGN] signal GLONASS
[Termes IGN] signal GPSRésumé : (Auteur) A study was conducted to empirically determine the degradation of survey-grade GPS horizontal position measurements due to the effects of broadleaf forest canopies. The measurements were taken using GPS/GLONASS-capable receivers measuring C/A and P-codes, and carrier phase. Fourteen survey markers were chosen in central Connecticut to serve as reference makers for study. These markers had varying degrees of sky obstruction due to overhanging tree canopies. Sky obstruction was measured by photographing the sky with a 35 mm reflex camera fitted with a hemispherical lens. The negative was scanned and the image mapped using an equal-area projection to remove the distortion caused by the lens. The resulting digital image was thresholded to produce a black-and-white image in which a count of the black pixels is a measure of sky-area obstruction. The locations of the markers were determined independently before the study. During the study, each marker was occupied for four 20-minutes sessions over the period of one week in mid-july 1999. The locations of the study markers produced relatively long baselines, as compared with similar studies. We compared the accuracy of GPS-only vs. GPS&GLONASS as a function of sky obstruction. Based on our results, GLONASS observations did not improve of degrade the accuracy of the position measurements. There is a loss of 2 mm of accuracy per percent of sky obstruction for both GPS only and GPS&GLONASS. Numéro de notice : A2002-360 Affiliation des auteurs : non IGN Thématique : FORET/POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22271
in Surveying and land information systems > vol 62 n° 4 (01/12/2002) . - pp 215 - 224[article]Utilisation combinée des techniques GPS et radar / C. Hagin in XYZ, n° 93 (décembre 2002 - février 2003)
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Titre : Utilisation combinée des techniques GPS et radar Type de document : Article/Communication Auteurs : C. Hagin, Auteur ; P. Lathion, Auteur Année de publication : 2002 Article en page(s) : pp 43 - 46 Langues : Français (fre) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] avalanche
[Termes IGN] écho radar
[Termes IGN] image radar
[Termes IGN] manteau neigeux
[Termes IGN] positionnement par GPS
[Termes IGN] radar pénétrant GPR
[Termes IGN] récepteur GPS
[Termes IGN] surveillance météorologique
[Termes IGN] temps réelRésumé : (Auteur) Au début des années 90, les récepteurs GPS étaient des instruments de mesure révolutionnaires dans nos professions, destinés presque exclusivement à des applications géodésiques en post-traitement. Au fil de l'évolution technologique, de nouveaux constructeurs sont apparus, qui ont diversifié et accru les fonctions et les possibilités des récepteurs. Les applications GPS en temps réel ont rapidement pris le pas sur le post-traitement, et de plus en plus de récepteurs bon marché ouvrent de nouvelles perspectives dans le vaste domaine de la navigation et du guidage de personnes ou de mobiles. Aujourd'hui, le GPS est devenu une technique courante du géomaticien, qui est aussi utilisé de plus en plus en combinaison avec d'autres capteurs. Ce travail d'intégration permet de géoréférencer à l'aide du GPS les données fournies par les capteurs, et par conséquent de réaliser des cartographies thématiques. Cette méthodologie est utilisée par exemple pour les applications bathymétriques, par couplage d'un système GPS et d'un échosondeur, ou pour les assainissements de décharge en combinant un capteur de gaz au GPS. Dans cet article, nous proposons de présenter plus en détail l'intégration d'un radar au GPS destinée à la surveillance aérienne du manteau neigeux. Numéro de notice : A2002-302 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22213
in XYZ > n° 93 (décembre 2002 - février 2003) . - pp 43 - 46[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 112-02041 RAB Revue Centre de documentation En réserve L003 Disponible 0,99999999 confidence ambiguity resolution with GPS and Galileo / Christian Tiberius in GPS solutions, vol 6 n° 1-2 (November 2002)
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Titre : 0,99999999 confidence ambiguity resolution with GPS and Galileo Type de document : Article/Communication Auteurs : Christian Tiberius, Auteur ; B. Pany, Auteur ; Bernd Eissfeller, Auteur ; P. Joosten, Auteur ; Sandra Verhagen, Auteur Année de publication : 2002 Article en page(s) : pp 96 - 99 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] ambiguïté entière
[Termes IGN] constellation GPS
[Termes IGN] Galileo
[Termes IGN] Global Positioning System
[Termes IGN] positionnement différentiel
[Termes IGN] résolution d'ambiguïté
[Termes IGN] secteur spatialRésumé : (Auteur) In this short contribution, it is demonstrated how integer carrier phase cycle ambiguity resolution will perform in near future, when the US GPS gets modernized and the european Galileo becomes operational. The capability of ambiguity resolution is analyzed in the context of precise differential positioning over short, medium and long distances. Starting from dual-frequency operation with GPS at present, particularly augmenting the number of satellites turns out to have beneficial consequences on the capability of correctly resolving the ambiguities. With a "double" constellation, on short baselines, the confidence of the integer ambiguity solution increases to a level of 0,99999999 or beyond. Numéro de notice : A2002-310 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-002-0022-6 En ligne : https://doi.org/10.1007/s10291-002-0022-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22221
in GPS solutions > vol 6 n° 1-2 (November 2002) . - pp 96 - 99[article] PermalinkOrthophoto generation using Ikonos imagery and high-resolution DEM: a case study on volcanic hazard monitoring of Nysoros island (Greece) / S. Vassilopoulou in ISPRS Journal of photogrammetry and remote sensing, vol 57 n° 1-2 (November - December 2002)
PermalinkIn step with INS-navigation for the blind tracking emergency crews / Q. Ladetto in GPS world, vol 13 n° 10 (October 2002)
PermalinkStaying afloat: GPS monitors oilfield subsidence / D. Rutledge in GPS world, vol 13 n° 10 (October 2002)
PermalinkA data model for multi-dimensional transportation applications / N. Koncz in International journal of geographical information science IJGIS, vol 16 n° 6 (september 2002)
PermalinkGPS at Ground zero: tracking world trade center recovery / R.J. Menard in GPS world, vol 13 n° 9 (September 2002)
PermalinkImprovement of GPS phase ambiguity resolution using prior height information as a quasi-observation / Jianjun Zhu in Geomatica, vol 56 n° 3 (September 2002)
PermalinkInfluence de la déviation de la verticale sur les travaux topographiques réalisés dans le système RGF93 / L. Andres in XYZ, n° 92 (septembre - novembre 2002)
PermalinkDigital surface model generation from CORONA satellite images / A. Altamaier in ISPRS Journal of photogrammetry and remote sensing, vol 56 n° 4 (July - August 2002)
PermalinkExperiences on operational GPS: inertial system calibration in airborne photogrammetry / Michael Cramer in GIS Geo-Informations-Systeme, vol 2002 n° 6 (Juni 2002)
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