Results 21 to 30 of about 742 (185)
Terrestrial, Atmospheric and Oceanic Sciences, 2011 The normal height H* is the height above the quasi-geoid, which coincides with the geoid in the ocean but slightly deviates from the geoid in terrestrial areas. In Mainland China, the height datum system is based on the quasi-geoid.
WenBin Shen +3 more
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Studia Geophysica et Geodaetica, 2006 The quasi-geoid/geoid can be determined from the Global Positioning System (GPS) ellipsoidal height and the normal/orthometric heights derived from levelling (GPS-levelling). In this study a gravimetric quasigeoid and GPS-levelling height differences are combined to develop a new surface, suitable for “levelling” by GPS.
Nahavandchi, Hossein, Soltanpour, Ali
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On the topographic bias and density distribution in modelling the geoid and orthometric heights
Journal of Geodetic Science, 2018 It is well known that the success in precise determinations of the gravimetric geoid height (N) and the orthometric height (H) rely on the knowledge of the topographic mass distribution.
Sjöberg Lars E.
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Geodesy and Geodynamics, 2015 Earth's gravity model (EGM) helps people better determine the figure of Earth, which is generally represented by a global geoid. For a considerable amount of practical applications, people use quasi-geoid to approximate the geoid, thus the quasi-geoid is
Jin Li, WenBin Shen, Xuhua Zhou
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Two alternative techniques for fitting the gravimetric geoid for Egypt
Contributions to Geophysics and Geodesy, 2023 In this paper, two proposed geoid fitting techniques for Egypt's gravimetrically determined geoid and Global Positioning System GPS/levelling-derived geoid are introduced. First, any errors in the available GPS stations are ruled out.
Hussein ABD-ELMOTAAL, Atef MAKHLOOF
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Geoid model validation and topographic bias
Journal of Geodetic Science, 2022 Recently a number of geoid campaigns were performed to verify different types of geoid and quasigeoid modeling techniques. Typically, GNSS-leveling was employed as an independent method, but in some cases zenith camera astronomic deflection data were ...
Sjöberg Lars E.
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Geodesy and GeodynamicsThe article presents a methodology for transitioning to the Amsterdam height system based on utilizing global and regional geoid/quasi-geoid models. The study was conducted for the Polish-Ukrainian cross-border sector and expanded to the entire territory
Alina Fedorchuk +2 more
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On geoid heights and flexure of the lithosphere at seamounts
Journal of Geophysical Research: Solid Earth, 1984 The sea surface height has now been mapped to an accuracy of better than ±1 m by using radar altimeters on board orbiting satellites. The major influence on the mean sea surface height is the marine geoid which is an equipotential surface. We have carried out preliminary studies of how oceanic volcanoes, which rise above the ocean floor as isolated ...
Watts, A, Ribe, N
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Journal of Geodetic Science, 2022 Following the definition and realization of the International Height Reference System (IHRS), the vertical coordinate of a given point at the Earth’s surface can be obtained from the computation of the geopotential value from a harmonic expansion of a ...
Tocho Claudia N. +4 more
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DFHRS-based computation of quasi-geoid of Latvia
Geodesy and Cartography, 2013 In geodesy, civil engineering and related fields high accuracy coordinate determination is needed, for that reason GNSS technologies plays important role.
Inese Janpaule +4 more
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