Performance evaluation of the Earth Gravitational Model 2008 (EGM2008) – a case study

Peprah, Michael Stanley; Ziggah, Yao Yevenyo; Yakubu, I

doi:10.4314/sajg.v6i1.4

Cited by 10 publications

(7 citation statements)

References 22 publications

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“…For obtaining orthometric heights (H), GNSS processing software uses a variety of global geopotential models. The EGM96 and EGM08 are two such models for determining the geoid height (N) which, as mentioned previously, are used to derive the orthometric height (H) from the GPS ellipsoidal height (h) (Peprah et al, 2017). The High Accuracy Reference Network (HARN) is made up of 30 stations, spaced approximately 200 kilometres apart across Egypt, and with a typical accuracy of 1: 10,000,000.…”

Section: N= H -Hmentioning

confidence: 99%

“…Several statistical indicators are used to assess the adequacy of the Earth Gravitational Models (EGMs) and the polynomial model. The Mean Error (ME), the Root Mean Square Error (RMSE), and the Standard Deviation (SD) are examples of these indicators (Peprah et al, 2017). The Root Mean Square Error (RMSE) is used to check the accuracy of the variations between a computed or measured value and an estimated value (Abdulrahman, 2021).…”

Section: Evaluating the Performance Of Earth Gravitational Models (Egms)mentioning

confidence: 99%

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Evaluation of EGM96 and EGM08 based on GPS/Levelling Heights in Egypt

Aziz¹,

Rashwan²,

Saba³

2023

SA J of Geomatics

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The heights determined by Global Positioning System (GPS) refer to the ellipsoid called the World Geodetic System 1984 (WGS84). Global Geopotential Models (GGMs) that are available on GNSS commercial software are generally used to transform ellipsoidal heights to orthometric heights. In this study, the geoid heights of GPS/Levelling were computed to evaluate the accuracy of the geoid heights obtained from two GGMs, namely, the Earth Gravitational Model 96 (EGM96) and the Earth Gravitational Model 08 (EGM08). Seventeen (17) GPS/Levelling stations of the High Accuracy Reference Network (HARN) over Egypt were used for this purpose. The standard deviations for the differences between the geoid heights obtained through GPS/Levelling and those obtained from EGM96 and EGM08 were determined as ± 1.212 m and ± 0.543 m, respectively. This research confirms that the geoid heights obtained from EGM08 are closer to the geoid heights determined using GPS/Levelling over Egypt.

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Section: N= H -Hmentioning

confidence: 99%

Section: Evaluating the Performance Of Earth Gravitational Models (Egms)mentioning

confidence: 99%

Evaluation of EGM96 and EGM08 based on GPS/Levelling Heights in Egypt

Aziz¹,

Rashwan²,

Saba³

2023

SA J of Geomatics

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“…Gravimetric measurements are absent for this area either. Many researchers have improved the working efficiency of global Earth gravitational models with the polynomial mathematical model (Peprah et al, 2017), GPS/leveling (Fazilova et al, 2020). The approach utilizes a network of points with known GPS/leveling height anomalies and the EGM96 model.…”

Section: H H N =+ Equationmentioning

confidence: 99%

Vertical Accuracy Assessment of Open Access Digital Elevation Models Using GPS

Fazilova

Magdiev²,

Sichugova

2021

IJG

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In this study, the vertical accuracy of the Shuttle Radar Topography Mission Digital Elevation Model Version 2.0 (SRTM30), the Advanced Spaceborne Thermal Emission and Reflection Radiometer Global DEM Version 2.0 (ASTER GDEM2), and Advanced Land Observing Satellite World 3D Digital Surface Model Version 2.1 (ALOS AW3D30) was statistically assessed using GPS data. The Tashkent geodynamical polygon was chosen as a study region, where the land surface can reflect as both natural (tectonic) and man-made (Charvak reservoir load effect) processes. The geometric approach using GPS/leveling stations and EGM96 GGM-based geoid undulations was applied for local geoid modeling. RMSE of ~7.48 m, ~6.90 m, and ~8.24 m was obtained for SRTM30, ASTER GDEM2, and ALOS AW3D30, respectively. ASTER GDEM2 proved to be the most accurate DEM with absolute vertical accuracy LE90 of 11.35 m and ME of 5.25 m and it is very suitable for geodetic and hydrological studies in this mountainous area.

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“…Using GPS/levelling data, several measured values to be interpolated are necessary: in the case of Izimir Municipality (Turkey), 1148 points were used as input dataset for an area covered by the grid of 12,648 sq km (Soycan, 2013). It is also possible to model the differences between the GPS/levelling undulations and the EGM2008 derived undulations at identified control points and then incorporate the resulting data into the global model (Peprah et al, 2017;Dawod, Mohamed, & Ismail, 2009). In this case, a smaller number of points can be used, considering that the global model covers the whole area.…”

Section: Ordinary Kriging Interpolatormentioning

confidence: 99%

“…The conversion of GPS (Global Positioning System) ellipsoidal height (h) into orthometric height requires a knowledge of the geoid undulation related to WGS84 ellipsoid (Featherstone, Dentith, & Kirby, 1998;Fotopoulos, Kotsakis, & Sideris, 2003;Kaplan & Hegarty, 2005;Shen & Han, 2013;Pepe, Prezioso, & Santamaria, 2015). In fact, a WGS84 ellipsoidal height is transformed to an orthometric height by algebraically subtracting have improved the working efficiency of EGM2008 with the polynomial mathematical model (Peprah, Ziggah, & Yakubu, 2017). By contrast, local geoid height models with more accurate grid spacing are determined, e.g., using GPS/levelling points, where both the ellipsoidal and orthometric heights are given; the first using GNSS technology, the latter derived from a surveying technique called "precise levelling".…”

Section: Introductionmentioning

confidence: 99%

Global Geoid Adjustment on Local Area for Gis Applications Using GNSS Permanent Station Coordinates

Falchi

Parente

Prezioso

2018

Geodesy and Cartography

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Orthometric heights, useful for many engineering and geoscience applications, can be obtained by GPS (Global Positioning System) surveys only when an accurate geoid undulation model (that supplies the vertical separation between the geoid and WGS84 ellipsoid) is available for the considered topic area. Global geoid height models (i.e., EGM2008), deriving from satellite gravity measurements suitably integrated with other data are free available on web, but their accuracy is often not sufficient for the user’s purposes. More accurate local models can nevertheless be acquired, but often only for a fee. GPS/levelling surveys are suitable for determining a local, accurate geoid model, but may be too expensive. This paper aims to demonstrate that GNSS (Global Navigation Satellite System) Permanent Station documents (monographs), freely available on the web and supplying orthometric and ellipsoidal heights, permit to calculate precise geoidal undulations useful to perform global geoid modelling on a local area. In fact, in this study 25 GNSS Permanent Stations (GNSS PS), located in North-Western Italy are considered: the differences between GNSS PS geoidal heights and the corresponding EGM2008 1′ × 1′ ones are used as a starting dataset for Ordinary Kriging applications. The resulting model is summed to the EGM2008 1′ × 1′, obtaining a better-performed model of the interest area. The accuracy tests demonstrate that the resulting model is better than EGM2008 grids to produce contours from a GPS dataset for large-scale mapping.

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Performance evaluation of the Earth Gravitational Model 2008 (EGM2008) – a case study

Abstract: Ghana's local geodetic reference network which is based on the War Office 1926 ellipsoid was established using astro-geodetic observations during the British

Cited by 10 publications

References 22 publications

Evaluation of EGM96 and EGM08 based on GPS/Levelling Heights in Egypt

Evaluation of EGM96 and EGM08 based on GPS/Levelling Heights in Egypt

Vertical Accuracy Assessment of Open Access Digital Elevation Models Using GPS

Global Geoid Adjustment on Local Area for Gis Applications Using GNSS Permanent Station Coordinates

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