Evaluation of EGM08 Using GPS and Leveling Heights in Greece

Kotsakis, C.; Katsambalos, K.; Ampatzidis, Dimitrios; Gianniou, M.

doi:10.1007/978-3-642-10634-7_64

Cited by 16 publications

(7 citation statements)

References 4 publications

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“…Orthometric heights (H) are then derived from ellipsoidal heights, by subtracting the geoidal undulation (N), i.e., H = h RMSE N [49]. Thus, for the present case study, N refers to the EGM2008 [50], from which the geoidal undulation accuracy in Greece is estimated with a standard deviation of approximately 15 cm [51][52][53]. With the above considerations and considering the error propagation, the RMSE of the overall original accuracy of the orthometric elevations for the GNSS points collected is in the order of 1 m.…”

Section: Horizontal and Vertical Datum Transformationsmentioning

confidence: 99%

European Digital Elevation Model Validation against Extensive Global Navigation Satellite Systems Data and Comparison with SRTM DEM and ASTER GDEM in Central Macedonia (Greece)

Mouratidis

Ampatzidis

2019

IJGI

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Digital elevation models (DEMs) are a widely used form of topographic information, with some of the most popular being the Shuttle Radar Topography Mission (SRTM) DEM and the Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model (ASTER GDEM). These two sources of topographical information are the main constituents of the European Union Digital Elevation Model (EU-DEM), which is a relatively new dataset of the EU’s Copernicus Land Monitoring Service. In this context, the purpose of this study was to validate EU-DEM for its vertical accuracy and to compare it with SRTM DEM and ASTER GDEM data. This was achieved in a Geographic Information System (GIS) environment, using extensive—in the order of tens of thousands of points—geodetic Global Navigation Satellite System (GNSS) measurements and appropriate pre-processing steps. The absolute elevation errors results had a Root Mean Square Error (RMSE) of 2.7 m at a 90% confidence level and characterize the performance of EU-DEM from local to regional scale, generally confirming that it is an enhanced source of elevation information when compared with its predecessors.

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Section: Horizontal and Vertical Datum Transformationsmentioning

confidence: 99%

European Digital Elevation Model Validation against Extensive Global Navigation Satellite Systems Data and Comparison with SRTM DEM and ASTER GDEM in Central Macedonia (Greece)

Mouratidis

Ampatzidis

2019

IJGI

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“…EGM2008 is a spherical harmonic model complete to degree and order of 2159, with additional spherical harmonic coefficients extending up to degree of 2190 and order 2159. This offers a spatial sampling resolution of approximately 9km for the recovery of gravity field functions over the entire globe (Kotsakis et al, 2008). EGM2008 incorporates 5x5 min gravity anomalies and altimetry-derived gravity anomalies and has benefited from the latest GRACE based satellite gravity field model (Pavlis et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…For this model to be used for geodetic activities anywhere on the globe, there is need to quantify its accuracy using several validation data sets such as geoid heights through the combination of GPS and levelling, airborne and local surface gravity measurements, marine geoid heights from mean oceanographic surface topography models and altimetry observations among others (Kotsakis et al, 2008;Kılıçoğlu et al, 2008). For better assessment, however, these external data sets should be independent of the estimation procedures that were used in the development of the model.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of EGM2008 by means of GPS Levelling Uganda

Abeho

Hipkin²,

Tulu³

2014

SA J of Geomatics

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The global gravity model EGM2008 is evaluated in various regions of Uganda to assess if it is good enough for geodetic applications. The evaluation method involves comparison of geoid heights computed from the model with those computed at irregularly distributed GPS Levelling stations. For testing the model, a total of seven levelled benchmarks available in Uganda which belong to the New Khartoum datum were used. The spatial positions of these benchmarks were determined at mm accuracy, with respect to ITRF2008. The agreement between the EGM2008 geoid and the geoid undulation derived from GPS Levelling over the seven irregularly distributed benchmark points has a standard deviation of 0.255m, with a mean of-0.859m. The datum offset may be due the choice of Wo (potential of the geoid) and Uo (potential on the surface of the ellipsoid); using GRS80 for the gravitational reference system and WGS84 for the geometrical reference system; some possibly different tidal conventions; but, by using the same method of analysis for Ethiopia and Uganda, these absolute offset effects are eliminated when comparing the two so that the computed difference [0.118m] in datum offset for the two states does tell us something about the differences in levelling datums. The standard deviation of 0.255m suggests that sparser, irregularly-distributed and inhomogenous gravity data for Uganda was used in the development of EGM2008 not ruling out errors in levelling since there is barely any documentation pertaining the accuracy of results obtained regarding the levelling network in Uganda.

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“…Moreover, because GGMs-derived geoid heights are referred to a global vertical datum and these are fitted with a local vertical datum by GPS/levelling-derived geoid heights, the accuracy of these (geoid heights) could be enhanced. For this purpose, leastsquares collocation (LSC) method is widely used (Kotsakis et al, 2008;Lee et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Implementation of the Distributed Parallel Program for Geoid Heights Computation Using Mpi and Openmp

Lee

Jung

Choi

et al. 2012

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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Much research have been carried out using optimization algorithms for developing high-performance program, under the parallel computing environment with the evolution of the computer hardware technology such as dual-core processor and so on. Then, the studies by the parallel computing in geodesy and surveying fields are not so many. The present study aims to reduce running time for the geoid heights computation and carrying out least-squares collocation to improve its accuracy using distributed parallel technology. A distributed parallel program was developed in which a multi-core CPU-based PC cluster was adopted using MPI and OpenMP library. Geoid heights were calculated by the spherical harmonic analysis using the earth geopotential model of the National Geospatial-Intelligence Agency(2008). The geoid heights around the Korean Peninsula were calculated and tested in diskless-based PC cluster environment. As results, for the computing geoid heights by a earth geopotential model, the distributed parallel program was confirmed more effective to reduce the computational time compared to the sequential program.

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Evaluation of EGM08 Using GPS and Leveling Heights in Greece

Cited by 16 publications

References 4 publications

European Digital Elevation Model Validation against Extensive Global Navigation Satellite Systems Data and Comparison with SRTM DEM and ASTER GDEM in Central Macedonia (Greece)

European Digital Elevation Model Validation against Extensive Global Navigation Satellite Systems Data and Comparison with SRTM DEM and ASTER GDEM in Central Macedonia (Greece)

Evaluation of EGM2008 by means of GPS Levelling Uganda

Implementation of the Distributed Parallel Program for Geoid Heights Computation Using Mpi and Openmp

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