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Improving the GNSS positioning stochastic model in the presence of ionospheric scintillation / M. Aquino in Journal of geodesy, vol 83 n° 10 (October 2009)  

Public [article]  inJournal of geodesy > vol 83 n° 10 (October 2009) . - pp 953 - 966 Titre : Improving the GNSS positioning stochastic model in the presence of ionospheric scintillation Type de document : Article/Communication Auteurs : M. Aquino, Auteur ; João F.G. Monico, Auteur ; A.H. Dodson, Auteur ; et al., Auteur Année de publication : 2009 Article en page(s) : pp 953 - 966 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] modèle stochastique [Termes IGN] positionnement par GNSS [Termes IGN] propagation ionosphérique [Termes IGN] récepteur GNSS [Termes IGN] scintillation [Termes IGN] teneur totale en électrons Résumé : (Auteur) Ionospheric scintillations are caused by time- varying electron density irregularities in the ionosphere, occurring more often at equatorial and high latitudes. This paper focuses exclusively on experiments undertaken in Europe, at geographic latitudes between ~50°N and ~80°N, where a network of GPS receivers capable of monitoring Total Electron Content and ionospheric scintillation parameters was deployed. The widely used ionospheric scintillation indices S4 and {\sigma_{\varphi}} represent a practical measure of the intensity of amplitude and phase scintillation affecting GNSS receivers. However, they do not provide sufficient information regarding the actual tracking errors that degrade GNSS receiver performance. Suitable receiver tracking models, sensitive to ionospheric scintillation, allow the computation of the variance of the output error of the receiver PLL (Phase Locked Loop) and DLL (Delay Locked Loop), which expresses the quality of the range measurements used by the receiver to calculate user position. The ability of such models of incorporating phase and amplitude scintillation effects into the variance of these tracking errors underpins our proposed method of applying relative weights to measurements from different satellites. That gives the least squares stochastic model used for position computation a more realistic representation, vis-a-vis the otherwise ‘equal weights’ model. For pseudorange processing, relative weights were com- puted, so that a ‘scintillation-mitigated’ solution could be performed and compared to the (non-mitigated) ‘equal weights’ solution. An improvement between 17 and 38% in height accuracy was achieved when an epoch by epoch differential solution was computed over baselines ranging from 1 to 750 km. The method was then compared with alternative approaches that can be used to improve the least squares stochastic model such as weighting according to satellite elevation angle and by the inverse of the square of the standard deviation of the code/carrier divergence (sigma CCDiv). The influence of multipath effects on the proposed mitigation approach is also discussed. With the use of high rate scintillation data in addition to the scintillation indices a carrier phase based mitigated solution was also implemented and compared with the conventional solution. During a period of occurrence of high phase scintillation it was observed that problems related to ambiguity resolution can be reduced by the use of the proposed mitigated solution. Copyright Springer Numéro de notice : A2009-430 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-009-0313-6 En ligne : https://doi.org/10.1007/s00190-009-0313-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30061 [article]

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266-09091	SL	Revue	Centre de documentation	Revues en salle	Disponible

The geomensor CR204 : baseline test results / A.H. Dodson in Survey review, vol 29 n° 229 (01/07/1988)  

Public [article]  inSurvey review > vol 29 n° 229 (01/07/1988) . - pp 351 - 357 Titre : The geomensor CR204 : baseline test results Type de document : Article/Communication Auteurs : A.H. Dodson, Auteur ; P. Fleming, Auteur Année de publication : 1988 Article en page(s) : pp 351 - 357 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Topographie [Termes IGN] base géodésique [Termes IGN] distancemètre [Termes IGN] étalonnage d'instrument Numéro de notice : A1988-238 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1179/sre.1988.29.229.351 En ligne : https://doi.org/10.1179/sre.1988.29.229.351 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=24817 [article]

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Code-barres	Cote	Support	Localisation	Section	Disponibilité
120-88031	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Refraction effects on precise EDM observations / J.C. Iliffe in Survey review, vol 29 n° 226 (01/10/1987)  

Public [article]  inSurvey review > vol 29 n° 226 (01/10/1987) . - pp 181 - 190 Titre : Refraction effects on precise EDM observations Type de document : Article/Communication Auteurs : J.C. Iliffe, Auteur ; A.H. Dodson, Auteur Année de publication : 1987 Article en page(s) : pp 181 - 190 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Topographie [Termes IGN] correction [Termes IGN] distancemètre [Termes IGN] Egypte [Termes IGN] Le Caire [Termes IGN] mesurage électronique de distances [Termes IGN] réfraction atmosphérique [Termes IGN] topométrie Numéro de notice : A1987-309 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1179/sre.1987.29.226.181 En ligne : https://doi.org/10.1179/sre.1987.29.226.181 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=24390 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
120-87041	RAB	Revue	Centre de documentation	En réserve L003	Disponible