High-precision quasi-geoid modeling using a small-parameter Molodensky's solution

Accurate quasi-geoid determination in rugged terrain remains a challenge in geodesy. A small-parameter solution is developed for Molodensky’s boundary value problem that enables direct and stable computation of the disturbing potential on topography. This methodology eliminates reduction-related assumptions and provides a theoretical foundation for quasi-geoid determination. Integrating airborne and terrestrial gravity data through a global gravity model, we achieve a centimeter-level quasi-geoid for Colorado. Validation against Geoid Slope Validation Survey 2017 benchmarks confirms 1.97 cm accuracy, outperforming conventional terrain-corrected approaches (2.44 cm). This work establishes a new method for quasi-geoid modeling, with implications for height system modernization in mountainous regions.