A GPS Height Fitting Method Based on the EGM2008 Model and Terrain Correction

GPS-derived height, due to the high efficiency and flexibility of GPS in engineering surveying, has been playing an important role under difficult environmental conditions. For applications in real projects, the geodetic height obtained by GPS should be transformed to normal height. The key issue in this transformation is to solve the height anomaly. This paper proposes a method to fit the residual height anomaly based on the EGM2008 model in combination with a separate terrain correction procedure. Datasets from an over-sea-bridge project were used to verify the performance of the proposed method. Numerical results show that, the proposed method can provide 0.16 cm accuracy for the points used for the fitting model determination and 0.96 cm accuracy for independent test points, and it can improve the precision of GPS height fitting.