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Corresponding Author

Mostafa Ashry

Subject Area

Civil and Environmental Engineering

Article Type

Original Study

Abstract

This study focuses on the establishment of a unified height system for Africa called AFRUHS (African Unified Height System) by utilizing atomic 8 clocks and clock networks. The International Association of Geodesy (IAG) has 9 long aims to construct an International Height Reference Frame (IHRF), but the lack of accurate and globally harmonized vertical coordinates, particularly in Africa, has posed a challenge. To overcome this, the researchers propose using clock networks to determine geopotential or elevation differences between distant stations by measuring the gravitational redshift (GR) through clock frequency comparisons. The research employs simulation studies using the ACES (Atomic Clock Ensemble in Space) and microwave signal communication to calculate the geopotential differences between ACES and three selected ground stations in Africa: Alexandria, Egypt (northeast); Dakar, Senegal (west); and Windhoek, Namibia (south).The study provides specific gravity level values and corresponding elevation differences for each of the three stations. For Alexandria Station, the gravity level is determined as 62636440.270 m2 s−2, with an elevation difference near the ground of 0.4 to 1.1 meters compared to the standard gravity level value. For Dakar Station, the gravity level is calculated as 62636652.310 m2s−2, with an elevation difference near the ground of 0.2 to 1.2 meters. Finally, Windhoek Station’s gravity level is estimated as 62620192.794 m2s−2, with an elevation difference near the ground of 0.6 to 0.9 meters. These findings highlight the potential of using clock networks and atomic clocks to establish an accurate and unified height system for Africa, contributing to the construction of the International Height Reference Frame.

Keywords

Africa, ACES mission · gravitational redshift · tri-frequency combination · frequency comparison · microwave links

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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