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Position: 20 kilometers, heavy construction: world's longest immersed tunnel, 40 meters underwater / A. Jensen in GPS world, vol 22 n° 5 (May 2011)

Public [article]  inGPS world > vol 22 n° 5 (May 2011) . - pp 30 - 37 Titre : Position: 20 kilometers, heavy construction: world's longest immersed tunnel, 40 meters underwater Type de document : Article/Communication Auteurs : A. Jensen, Auteur ; D. Hermsmeyer, Auteur ; et al., Auteur Année de publication : 2011 Article en page(s) : pp 30 - 37 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes IGN] Allemagne [Termes IGN] Danemark [Termes IGN] niveau moyen des mers [Termes IGN] positionnement cinématique en temps réel [Termes IGN] réseau géodésique spécifique [Termes IGN] station GNSS [Termes IGN] système de référence local [Termes IGN] tunnel Résumé : (Auteur) The Fehmarnbelt Positioning System between Denmark and Germany includes a geodetic basis, four permanent GNSS stations, and a real-time kinematic (RTK) service for construction of a road and rail causeway between the islands of Fehmarn, Germany, and Lolland, Denmark across the Fehmarnbelt, a 20-kilometer stretch of open water in the Baltic Sea. This homogeneous, consistent, coherent, highly accurate GNSS-based positioning system exemplifies comparable systems and services that can be established for any major construction site or infrastructure project. Now in use for environmental, geotechnical, and geophysical investigations, it provides cost-efficient operations and facilitates the precise navigation of large, costly offshore equipment. Numéro de notice : A2011-179 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30957 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
067-2011051	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Doppler-aided positioning: Improving single-frequency in the urban environment / M. Bahrami in GPS world, vol 22 n° 5 (May 2011)

Public [article]  inGPS world > vol 22 n° 5 (May 2011) . - pp 47 - 56 Titre : Doppler-aided positioning: Improving single-frequency in the urban environment Type de document : Article/Communication Auteurs : M. Bahrami, Auteur ; Marek Ziebart, Auteur Année de publication : 2011 Article en page(s) : pp 47 - 56 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes IGN] données Doppler [Termes IGN] effet Doppler [Termes IGN] géonavigateur [Termes IGN] lissage de données [Termes IGN] mesurage de pseudo-distance [Termes IGN] milieu urbain [Termes IGN] positionnement cinématique en temps réel [Termes IGN] récepteur monofréquence Résumé : (Editeur) What do a GPS receiver, a policeman’s speed gun, a weather radar, and some medical diagnostic equipment have in common? Give up? They all make use of the Doppler effect. First proposed in 1842 by the Austrian mathematician and physicist, Christian Doppler, it is the change in the perceived frequency of a wave when the transmitter and the receiver are in relative motion. Doppler introduced the concept in an attempt to explain the shift in the color of light from certain binary stars. Three years later, the effect was tested for sound waves by the Dutch scientist Christophorus Buys Ballot. [...] The beginning of the space age heralded a new application of the Doppler effect. By measuring the shift in the received frequency of the radio beacon signals transmitted by Sputnik 1 from a known location, scientists were able to determine the orbit of the satellite. And shortly thereafter, they determined that if the orbit of a satellite was known, then the position of a receiver could be determined from the shift. That realization led to the development of the United States Navy Navigation Satellite System, commonly known as Transit, with the first satellite being launched in 1961. Initially classified, the system was made available to civilians in 1967 and was widely used for navigation and precise positioning until it was shut down in 1996. The Soviet Union developed a similar system called Tsikada and a special military version called Parus. These systems are also assumed to be no longer in use — at least for navigation. GPS and other global navigation satellite systems use the Doppler shift of the received carrier frequencies to determine the velocity of a moving receiver. Doppler-derived velocity is far more accurate than that obtained by simply differencing two position estimates. But GPS Doppler measurements can be used in other ways, too. In this month’s column, we look at how Doppler measurements can be used to smooth noisy code-based pseudoranges to improve the precision of autonomous positioning as well as to improve the availability of single-frequency real-time kinematic positioning, especially in urban environments. Numéro de notice : A2011-180 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30958 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
067-2011051	RAB	Revue	Centre de documentation	En réserve L003	Disponible