A Compartmentalized Elevation Model Approach to Terrain Correction in Microgravity Surveys

Microgravity surveying is a high-resolution geophysical technique widely used for detecting subsurface voids, karst features, and localized density variations in engineering, environmental, and geological investigations. However, in complex environments such as steep mountainous terrain, narrow valleys, and urban or built-up areas, standard terrain correction approaches often fail to adequately account for fine-scale topographic variations and man-made structures. These limitations can introduce significant distortions in Bouguer anomalies, particularly at the microGal sensitivity level required for microgravity applications.

This research presents an enhanced terrain correction methodology specifically tailored for microgravity surveys conducted in complex natural and artificial environments. The proposed approach integrates high-resolution elevation data derived from Digital Terrain Models (DTMs), conventional topographic surveys, and 3D LiDAR datasets to construct detailed compartmentalized mass models around each gravity observation point. Surrounding terrain and structures are discretized into three-dimensional volumetric compartments characterized by spatial position, elevation, size, and density. Unlike conventional methods, the approach allows the assignment of variable densities to individual compartments, enabling accurate representation of heterogeneous materials such as rock, air-filled voids, buildings, and structural components.

Gravitational acceleration contributed by each compartment is calculated using Newtonian gravity principles, and the vertical component relevant to terrain correction is extracted and summed to compute station-specific corrections. The methodology is implemented using a database-driven computational framework to efficiently handle the large number of calculations involved. Results demonstrate that the proposed technique significantly improves terrain correction accuracy, effectively capturing the gravitational influence of steep slopes, narrow valleys, and complex urban infrastructure. The integration of 3D LiDAR-derived models enhances spatial resolution and supports microGal-level precision. The proposed compartmentalized terrain correction approach provides a scalable, automated, and accurate alternative to traditional methods, offering substantial benefits for microgravity investigations in rugged terrain and densely built environments.