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Auteur Markus Rothacher |
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Accuracy and biases in the geodetic application of the Global Positioning System / Gerhard Beutler (01/01/1987)
contenu dans GPS-Papers presented by the astronomical institute of the university of Berne in the year 1987 / Werner Gurtner (1987)
Titre : Accuracy and biases in the geodetic application of the Global Positioning System Type de document : Article/Communication Auteurs : Gerhard Beutler, Auteur ; Ivo Bauersima, Auteur ; Serge Botton , Auteur ; Werner Gurtner, Auteur ; Markus Rothacher, Auteur ; Thomas Schildknecht, Auteur Editeur : Berne : Université de Berne Année de publication : 01/01/1987 Conférence : IUGG 1987, 19th General Assembly 09/08/1987 22/08/1987 Vancouver Canada Importance : pp 1 - 8 Format : 21 x 30 cm Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] erreur de positionnement
[Termes IGN] positionnement par GPS
[Termes IGN] précision géométrique (imagerie)Résumé : (Auteur) Abstract.GPS results may be biased by environmental effects (atmosphere), by orbit errors, by erroneous station coordinates kept fixed, and by physical parameters (e.g. GM-value). First we summarize the influence of unmodeled biases on GPS results and then we demonstrate the benefit of correct modeling. Special attention is paid to the scale of GPS results, which is essentially defined by the numerical value for the speed of light c, but which may be biased by an erroneous GM-value and a wrong teight of the station(s) kept fixed. We show that biases introduced by today's uncertainties in these quantities are of the order of less than 0.01 ppm. In order to assess GPS accuracies we need independent information. Terrestrial surveys may provide that for small scale (10 km x 10 km), VLBI for large scale applications. We show that today GPS accuracies are comparable with those obtained using the most sophisticated terrestrial techniques in small scale applications (provided the troposphere is modeled in an appropriate, way) and with those obtained using mobile VLBI technique in large scale applications (provided the orbits are modeled correctly). Finally we give an empirical formula for the accuracy of GPS as a function of the network size. Numéro de notice : C1987-109 Affiliation des auteurs : IGN+Ext (1940-2011) Thématique : POSITIONNEMENT Nature : Communication DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=65294 The use of the Global Positioning System in mountainous areas / Gerhard Beutler (01/01/1987)
contenu dans GPS-Papers presented by the astronomical institute of the university of Berne in the year 1987 / Werner Gurtner (1987)
Titre : The use of the Global Positioning System in mountainous areas Type de document : Article/Communication Auteurs : Gerhard Beutler, Auteur ; Ivo Bauersima, Auteur ; Serge Botton , Auteur ; Werner Gurtner, Auteur ; Markus Rothacher, Auteur Editeur : Berne : Université de Berne Année de publication : 01/01/1987 Conférence : IUGG 1987, 19th General Assembly 09/08/1987 22/08/1987 Vancouver Canada Importance : pp 1 - 21 Format : 21 x 30 cm Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] montagne
[Termes IGN] positionnement par GPSRésumé : (Auteur) In 1985 and 1986 a high precision terrestrial 3D network (8 stations, 5kmx6kmxlkm) was established in the Swiss 'alps. The three-dimensional adjustment of the terrestrial measurements (EDM, atmospheric data along the light beam, multicolor EDM, horizontal and vertical angles, leveling, local geoid model) shows standard deviations of the order of lmm in horizontal and a few millimeters in vertical positions. So far two GPS campaigns were organized in October 1985 and in October 1986. Five receiver types (Macrometer V-1000, Sercel TR5S, TI-4100, Trimble 4000S, WM-101) give formal accuracies of the order of lmm in horizontal an 2mm in vertical position. Combined GPS solutions show an agreement of the order of lmm to 2mm in horizontal position with the terrestrial solution. The situation is more complex in vertical position due to the troposphere. We present different ways to model tropospheric refraction using either a standard atmosphere or meteo values measured at the receiver sites or meteo profiles recorded on a cableway. Moreover we discuss possibilities to estimate troposphere parameters from GPS carrier phase data (simultaneously with site coordinates). Depending on the method chosen to account for the troposphere we obtain an agreement with the terrestrial solution of 50mm, to 5mm in height. Numéro de notice : C1987-108 Affiliation des auteurs : IGN+Ext (1940-2011) Thématique : POSITIONNEMENT Nature : Communication DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=65293