A Comparative Study of Different Geodetic Boundary Value Solutions for Geoid with reference to its Calibration Using GPS/Leveling Data

The equipotential geoid of the gravity field of the Earth can be modeled with different formulation of the geodetic boundary value problems and their solutions. These techniques range from Helmert´s 2nd method of condensation to Residual terrain modeling and then to the Molodenskij solution of the geodetic boundary value problem. The available data for gravity anomalies, elevation and their distribution within Pakistan requires careful study and selection from these solution methods. This study involves the comparison and discussion of different geoid modeling techniques with the geoid determined from GPS / Leveling data. Each of the above mentioned techniques has some advantages and drawbacks due to their data requirement, computational technique and validation of results. This calibration study will help to establish the selection of the suitable method for extended study of geoid model all over Pakistan. These techniques were implemented and tested in central area of Pakistan having diverse landscape with elevation range from 106m to 1522m above mean sea level. A statistical 3D regression model was developed for the compensation of offset between different geoidal solutions.