Calculation of a quasi-geoid model based on the scalar-free solution of the Geodetic Boundary Value Problem (GBVP) with numerical integration of Stokes integrals within the Colorado Experiment

Abstract

Abstract: This paper presents the approach proposed by UFPR for calculating a quasi-geoid model within the Colorado Experiment (CE) based on the scalar-free solution of the Geodetic Boundary Value Problem (GBVP), using Molodensky series and numerical solutions of Stokes integrals. The study area covers part of the state of Colorado, USA, where fourteen different research groups sought to model the Earth’s gravity field with centimeter precision. The model was calculated from residual Molodensky gravity anomaly values, calculated using available ground and airborne data, using the Remove-Compute-Restore (RCR) technique. Tests were conducted to identify the optimal Wong and Gore (WG) modification degree and cap size to best fit the model to the GSVS17 reference data. Analysis of the results revealed that the model had a standard deviation of 2.7 cm, an RMSE of 86.4 cm, and lower variability compared to solutions from the other 12 institutions. It was also found that the solution is significantly influenced by changes in the Wong and Gore modification degree. The study concludes that the solution proposed here is an effective alternative for calculating quasi-geoid models and for point-based geopotential modeling within the scope of International Height Reference Frame (IHRF) implementation, even in areas with complex topography.