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

Aziz, Khaled Mahmoud Abdel; Rashwan, Karim Samir; Saba, Nasr

doi:10.4314/sajg.v12i1.3

Cited by 2 publications

(3 citation statements)

References 6 publications

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“…The results in table (1) showed that the biggest RMS values of the ten tested GGMs was in USA, and they range from 0.246 to 0.264 m. Recalling that [1] tested EGM2008 at the 17 HARN stations and the standard deviation of the differences was 0.543 m, and [12] tested GECO at the 17 HARN stations and the standard deviation of the differences was 0.42 m which matches the results here.…”

Section: Resultssupporting

confidence: 80%

“…Where N is the geoid height, h is the ellipsoidal height determined from GPS, and H is the orthometric height determined from the levelling process, see Figure (1).…”

Section: Geoid Orthometric and Ellipsoidal Heightsmentioning

confidence: 99%

“…These ten models were chosen based on the best accuracy of the results obtained from these models in many countries such as Mexico, USA, Canada, Brazil, Australia, Europe, and Japan, see Table (1).…”

Section: Introductionmentioning

confidence: 99%

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Assessment of some global geopotential models over Egypt and the Kingdom of Saudi Arabia

Abdel Aziz

2023

Engineering Research Journal (Shoubra)

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Orthometric heights related to the geoid, are important in many engineering projects. The use of Global Positioning System (GPS) does not give the heights of the points on the surface of the geoid but gives them on the surface of the reference ellipsoid. Geoid undulations should be offered to obtain the needed orthometric heights from their corresponding available ellipsoidal heights. The aim of this research is to obtain the best among the Global Geopotential Models (GGMs) that give the results closest to the observed geoid heights over two study areas. Firstly, in Egypt and secondly in the Kingdom of Saudi Arabia (KSA). In the first study area, RMS of the differences between the observed undulations (GPS/levelling) and those from GOCO05c, XGM2016, and GECO are the lowest values among the ten tested GGMs. In the second study area, RMS of the differences between the undulations from KSA-GEOID21 and those from XGM2019e_2159, XGM2016, and XGM2019 are the lowest among the ten tested GGMs.

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Section: Resultssupporting

confidence: 80%

“…Where N is the geoid height, h is the ellipsoidal height determined from GPS, and H is the orthometric height determined from the levelling process, see Figure (1).…”

Section: Geoid Orthometric and Ellipsoidal Heightsmentioning

confidence: 99%

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Assessment of some global geopotential models over Egypt and the Kingdom of Saudi Arabia

Abdel Aziz

2023

Engineering Research Journal (Shoubra)

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Studying the Ephemeris Effect on Position Accuracy Based on Criteria Applied to Baseline Lengths by New MATLAB Program (NMP)

Farouk,

El-Nokrashy,

Abd-Elhay

et al. 2023

J. Astron. Space Sci.

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Although the Relative Global Navigation Satellite System (GNSS) positioning technique provides high accuracy, it has several drawbacks. The scarcity of control points, the long baselines, and using of ultra-rabid and rabid products increased position errors. This study has designed a New MATLAB Program that helps users automatically select suitable IGS stations related to the baseline lengths and the azimuth between GNSS points and IGS stations. This study presented criteria for the length of the baselines used in Egypt and an advanced estimated accuracy before starting the project. The experimental test studies the performance of the position accuracy related to the relation between three factors: observation session, final, rabid, and ultra-rabid products, and the baseline lengths. Ground control point mediates Egypt was selected as a test point. Nine surrounding IGS stations were selected as reference stations, and the coordinates of the tested point were calculated based on them. Baselines between the tested point and the IGS stations were classified regarding proposal criteria. The coordinates of the tested point were obtained in different observation sessions (0.5, 1, 2, 4, 5, 6, 7, 7.5 h). The results indicated that the lengths of the baseline in Egypt were classified short (less than 600 km), medium (600–1,200 km), and long (greater than 1,200 km) and required a minimum observation time of 4, 5, and 7 h to obtain accuracy 10, 19, 48 mm sequentially. The position accuracy was superior for the rapid and the final than the ultra-rapid products by 16%. A short baseline was at the best case; there was a performance in position accuracy with a 57% deduction in observation time compared with the long baseline.

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

Cited by 2 publications

References 6 publications

Assessment of some global geopotential models over Egypt and the Kingdom of Saudi Arabia

Assessment of some global geopotential models over Egypt and the Kingdom of Saudi Arabia

Studying the Ephemeris Effect on Position Accuracy Based on Criteria Applied to Baseline Lengths by New MATLAB Program (NMP)

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