Airborne Gravity Data Reconstruction Strategies for Geoid Optimization in Peninsular Malaysia

Abstract

Geoid height is essential for precise height determination, particularly in surveying and geodetic applications. Airborne gravity data substantially improve geoid models, especially over regions with complex terrain where terrestrial coverage is limited. However, since airborne data are acquired at flight altitude, they require downward continuation to the geoid surface which an inherently unstable process. Despite ongoing advancements, the most effective strategy for combining and gridding gravity data, particularly airborne measurements, remains a topic of research. This study evaluates two downward continuation strategies to assess their influence on geoid accuracy. The first strategy applies downward continuation to airborne data simultaneously with terrestrial and marine data, incorporating a range of buffer distances (0 km, 1 km, 5 km, and 10 km) to examine their effect on model performance. The second strategy involves performing downward continuation on airborne data independently before merging with other datasets. Numerical results indicate the Root Mean Square Error (RMSE) values of 0.044 m for the first strategy and 0.045 m for the second, with a marginal difference of 0.001 m. Although the difference appears minor, even marginal improvements can be pivotal in high-precision geoid modelling particularly in localized regions where complex topography or sparse data coverage may magnify subtle errors. Such refinements are essential to advancing the long-term goal of achieving geoid accuracy at the 1 cm level for Peninsular Malaysia. © Geoinformatics International.