Results 131 to 140 of about 20,151 (197)

Modelling local GPS/levelling geoid undulations using artificial neural networks

Journal of Geodesy, 2005
The use of GPS for establishing height control in an area where levelling data are available can involve the so-called GPS/levelling technique. Modelling of the GPS/levelling geoid undulations has usually been carried out using polynomial surface fitting, least-squares collocation (LSC) and finite-element methods. Artificial neural networks (ANNs) have
T. Kavzoglu, M. H. Saka
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Methods for the computation of geoid undulations from potential coefficients

Bulletin géodésique, 1971
The undulations of the geoid may be computed from spherical harmonic potential coefficients of the earth’s gravitational field. This paper examines three procedures that reflect various points of view on how this computation should be carried out. One method requires only the flattening of a reference ellipsoid to be defined while the other two methods
R. Rapp
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GEOID UNDULATION D IFFERENCES B ETWEEN GEOPOTENTIAL MODELS

Surveys in Geophysics, 1993
Three geopotential models (OSU91A, GEM-T3, and GRIM4-C2), available in 1991, have been compared in several ways. The models have been differenced to find the geoid undulation difference are on the order of 1 m in land areas and 30 cm in ocean areas with extreme differences reaching 6 m.
Richard H. Rapp, Yan Ming Wang
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Regional Geoid Undulations from CHAMP, Represented by Locally Supported Basis Functions

2005
Regional geoid undulations are determined from CHAMP data using various locally supported basis functions to assess their respective efficiency, accuracy and multi-resolution representation properties. These functions include (biharmonic) B-spline tensor wavelets (with or without compression), multiquadrics (with or without flexible centering and ...
Rainer Mautzl, Burkhard Schaffrin, C. K. Shum, Shin-Chan Han   +3 more
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The determination of geoid undulations and gravity anomalies from SEASAT altimeter data

Journal of Geophysical Research: Oceans, 1983
The global SEASAT altimeter data set has been edited and adjusted using a crossing arc procedure fixing one long arc to provide control. In doing this a set of 168 master arcs were formed from repeat and near repeat arcs. The adjustment, carried out by D. Rowlands, was done in a global net, and four regional areas.
R. Rapp
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General Scheme for the Computation of Regional Geoid Undulations Using Spherical Wavelets

2002
Usually the geoid undulations are modelled by means of an expansion in terms of spherical harmonics. One of the most important disadvantages of this representation is the fact that local changes of the geoid affect all coefficients. Thus, an appropriate model of the geoid undulations may consist of an expansion in terms of spherical harmonics for the ...
M. Schmidt, W. Martínez, J. Florez
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Regional Gravity Anomalies and Geoid Undulations in the North Atlantic Ocean

CRC Handbook of Geophysical Exploration at Sea, 2019
Woo-Yeol Jung, Philip D. Rabinowitz
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Free-Air Gravity Anomalies Caused by the Gravitational Attraction of Topographic, Bathymetric Features, and Their Isostatic Compensating Masses And Corresponding Geoid Undulations

, 2011
L. A. Kivioja, Albert D. M. Lewis
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Minimization and estimation of geoid undulation errors

Bulletin Géodésique, 1994
The objective of this paper is to minimize the geoid undulation errors by focusing on the contribution of the global geopotential model and regional gravity anomalies, and to estimate the accuracy of the predicted gravimetric geoid. The geopotential model's contribution is improved by (a) tailoring it using the regional gravity anomalies and (b ...
Ye Cai Li, Michael G. Sideris
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Determination of Geoid Undulation by Astro-Geodetic Method

Journal of Surveying Engineering, 2016
AbstractCivil engineering projects require the orthometric height of points (i.e., the height of points above geoid). Thus, to make use of the Global Navigation Satellite System (GNSS) in engineering surveying, geoid undulation (i.e., the separation between an ellipsoid and geoid surface) must be known.
Jayanta Kumar Ghosh, Upendra Nath Mishra
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