Assessment of Orthometric Height Derived from Levelling, GNSS and EGM2008 Geoid Model in Bangladesh

Sikder, Muhammad Abdul Alim; Wu, Falin; Ahmed, Wasiu Akande; Thodsan, Thippawan; Zhao, Yan

doi:10.1109/icsp48669.2020.9321048

Cited by 5 publications

(3 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The results clearly showed that EGM08 represents the most precise GGM to be used for determining geoid heights in Egypt. Sikder et al (2020) obtained the RMSE, the mean and the standard deviation of EGM2008 in Bangladesh, are , 0.1757 m, 0.1718 m and 0.0376 m, respectively, for fifteen GNSS/levelling stations. In India, Rao et al (2012), the use of the GPS/levelling stations to assess the EGM96 and EGM08 in two study areas, established that the RMSE of the EGM96 for the two study areas (1) and (2) was 1.41m and that the RMSE of the EGM08 was 0.5 m for study area (1) and 0.6 m for study area (2).…”

Section: N= H -Hmentioning

confidence: 88%

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

Aziz¹,

Rashwan²,

Saba³

2023

SA J of Geomatics

View full text Add to dashboard Cite

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.

show abstract

Section: N= H -Hmentioning

confidence: 88%

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

Aziz¹,

Rashwan²,

Saba³

2023

SA J of Geomatics

View full text Add to dashboard Cite

show abstract

“…al, 2018;Oluyori et. al, 2018;Sikder et. al, 2020), there has been no research on this topic in Nepal.…”

Section: Introductionmentioning

confidence: 98%

Can GNSS Derived Height Replace Levelling Height? - A Case of Low-Land of Nepal

KC¹,

Bhandari²,

Upadhyaya³

et al. 2023

J. Geoinformatics, Nep.

View full text Add to dashboard Cite

Orthometric height is the generally adopted type of height worldwide and in geomatics community. Precise levelling has been the method of obtaining orthometric height in past for most of the country, so as the Nepal. However, due to wide usage of Global Navigation Satellite System (GNSS), the alternative approach of combining GNSS derived ellipsoidal height with geoid undulation to get GNSS derived orthometric height, has been used extensively. In Nepal, this technique was officially adopted in 2020 for Everest height measurement and understood as the efficient way to comply with levelling height. In this study, GNSS surveying was conducted on 15 stations located at the lowland region of Nepal and orthometric heights were obtained from GNSS and geoid method. When compared GNSS derived orthometric height with precise levelling height, the difference remained within threshold of 5cm for majority of observation stations. However, these differences are not sufficient to support the standards set for the third order levelling by Survey Department (SD). The accuracy of GNSS derived orthometric height can be significantly affected by various environment and existing resources such as existing accuracy of geoid, nature of precise levelling height. Considering the revisit upon these conditions, we expect GNSS-levelling as a strong alternative to time consuming, tedious, and costly precise levelling which is most suitable method of obtaining orthometric height in lowland topography at a precision less than 4 cm.

show abstract

“…Thus, spirit leveling has been continuously used to determine (orthometric) height so as to coincide with the local vertical datum in each case and to ensure precision, despite the widespread use of GNSS in the field of surveying. However, GNSS-derived height determination, which is a modern technique that calculates elevation as the difference between the ellipsoidal and geoidal heights, is now being used, following the development of a precise local geoid [1][2][3][4][5][6]. To make it clear, the technique to calculate the elevation based on GNSS and the geoid model is called GNSS-derived height determination, and the calculation result is called elevations in this study.…”

Section: Introductionmentioning

confidence: 99%

Analyzing Precision and Efficiency of Global Navigation Satellite System-Derived Height Determination for Coastal and Island Areas

2021

View full text Add to dashboard Cite

The global navigation satellite system (GNSS)-derived height determination technique is applied in the field of surveying owing to the broad use of GNSS and the development of precise local geoid models. In Korea, this technique was officially adopted in 2020 for public surveying, such as urban facility mapping; it is also treated as an efficient way to unify the vertical datum of the inland and island areas of Korea. Here, GNSS surveying was conducted on 19 stations located in Korea’s coastal regions and islands, and GNSS-derived elevations were determined. When each GNSS-derived elevation was compared with elevations from spirit leveling, all stations showed differences of less than 3 cm when GNSS surveying was conducted for 4 h/day over two days; they were smaller than 5 cm with 2 h of surveying. These differences meet the standards of GNSS-derived elevations in Korea. In addition, GNSS-derived elevations were compared with those obtained via sea-crossing leveling in two regions, showing differences smaller than 1 cm. Sea-crossing leveling takes longer than GNSS-derived height determination, and its accuracy can be significantly affected by various environments, such as sea fog. Thus, GNSS-derived height determination represents a practical and useful technique.

show abstract

Assessment of Orthometric Height Derived from Levelling, GNSS and EGM2008 Geoid Model in Bangladesh

Cited by 5 publications

References 13 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

Can GNSS Derived Height Replace Levelling Height? - A Case of Low-Land of Nepal

Analyzing Precision and Efficiency of Global Navigation Satellite System-Derived Height Determination for Coastal and Island Areas

Contact Info

Product

Resources

About