Advanced Geoid Modeling in Sulawesi and Accuracy Verification Strategies for Accommodating Diverse MSL Vertical Datums

Abstract

This study aims to improve the accuracy of the geoid model in Sulawesi, which is crucial for converting GNSS-observed ellipsoid heights to orthometric heights. There are limitations of terrestrial gravity surveys in Indonesia due to its complex geography, so airborne gravity surveys were conducted from 2008 to 2019 through a collaboration between BIG, the Technical University of Denmark (DTU), and the National Chiao Tung University (NCTU) gravity research team. The airborne gravity data currently cover almost the entire land area of ​​Indonesia. The geoid modeling process involved refining the EGM08-derived geoid heights by incorporating downward-continued airborne gravity data and RTM-derived geoid effects and adjusting the geometric geoid heights to accommodate variations in the mean sea levels observed in different GPS/leveling datasets. The study revealed that airborne gravity data significantly improved the accuracy of the geoid, achieving an impressive accuracy of approximately 0.04 cm. Additionally, this study examined the impacts of different global gravitational models (GGMs), such as EIGEN-6C4, GECO, XGM2019e, and SGG-UGM-2, on geoid modeling and revealed that differences arise from the different datasets used in the development process of the GGM. The modeling approach significantly improves the accuracy of the geoid from decimeter-level accuracy to centimeter-level accuracy. Accurate geoids are critical for infrastructure development, land-use planning, and resource management and play an integral role in supporting sustainable development goals (SDGs) by providing accurate spatial referencing, ensuring precise mapping, and offering location-based services.