Combination Schemes for Local Orthometric Height Determination from GPS Measurements and Gravity Data

One of the most interesting and challenging tasks in the field of geodetic surveying is the accurate determination of orthometric heights from GPS measurements taking into account leveling data and additional gravity field information. This paper focuses on the presentation of the currently available various solution strategies which are then properly applied. The first method is based on the integrated geodetic model, where gravity field parameters are treated as signals. A second solution is based on a combination scheme employing least squares collocation as the optimal heterogeneous combination method for gravity and height data. Another method is the spectral domain equivalent of least squares collocation, namely the Multiple Input Multiple Output System Theory, where gravity and height data are treated as stochastic signals with full variance covariance information. The last method consists in a polynomial interpolation model of various orders expressing different geoid representations.