A high-accuracy and high-resolution gravimetric geoid is crucial for a wide range of geoscientific and engineering projects, hence the State Authority for Geospatial Information (ASIG) of the Republic of Albania, has initiated a project to modernize the country’s gravity infrastructure. As part of this effort, 934 new high-quality land gravity benchmarks have been observed and realized between 2022–2024. These newly acquired observations have been combined with historical gravity data in the mainland of Albania, satellite altimetry data for marine areas and EGM2008 as fill-in for the surrounding countries to calculate a new gravimetric geoid model. The geoid determination was carried out employing the well-known remove-compute-restore technique with the Global Geopotential Model (GGM) contribution evaluated from the latest combined models, EIGEC6c4 and XGM2019e, while for topographic effects, both spectral and classical approaches were tested. The final estimation was carried out using both Least Squares Collocation (LSC) and Stokes’s Integral method, while the validation was performed against a set of 225 GNSS-levelling BMs, where both ellipsoidal and orthometric heights were available. The FFT-based geoid achieved a mean difference at the 0.2 cm level, a standard deviation of 13.1 cm, relative differences over the measured levelling benchmarks at the 15.83 ppm for baselines between 0–10 km. Finally, after a deterministic fit to the GNSS-levelling data, the fitted geoid reached absolute accuracies at the 11.5 cm, relative accuracies at the 10 ppm for baselines as short as 10–20 km, and 48.9% of the differences being below the 10 ppm level.

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A New Gravimetric and Hybrid Geoid Model in Albania

  • D. A. Natsiopoulos,
  • G. S. Vergos,
  • Kristaq Qirko,
  • Oltjon Balliu,
  • Endri Qershija,
  • Luciano Kasnec,
  • Perparim Ndoj

摘要

A high-accuracy and high-resolution gravimetric geoid is crucial for a wide range of geoscientific and engineering projects, hence the State Authority for Geospatial Information (ASIG) of the Republic of Albania, has initiated a project to modernize the country’s gravity infrastructure. As part of this effort, 934 new high-quality land gravity benchmarks have been observed and realized between 2022–2024. These newly acquired observations have been combined with historical gravity data in the mainland of Albania, satellite altimetry data for marine areas and EGM2008 as fill-in for the surrounding countries to calculate a new gravimetric geoid model. The geoid determination was carried out employing the well-known remove-compute-restore technique with the Global Geopotential Model (GGM) contribution evaluated from the latest combined models, EIGEC6c4 and XGM2019e, while for topographic effects, both spectral and classical approaches were tested. The final estimation was carried out using both Least Squares Collocation (LSC) and Stokes’s Integral method, while the validation was performed against a set of 225 GNSS-levelling BMs, where both ellipsoidal and orthometric heights were available. The FFT-based geoid achieved a mean difference at the 0.2 cm level, a standard deviation of 13.1 cm, relative differences over the measured levelling benchmarks at the 15.83 ppm for baselines between 0–10 km. Finally, after a deterministic fit to the GNSS-levelling data, the fitted geoid reached absolute accuracies at the 11.5 cm, relative accuracies at the 10 ppm for baselines as short as 10–20 km, and 48.9% of the differences being below the 10 ppm level.