Compare With EGM2008 EGM96 Gravity Field Models And Evaluation In Yunnan

The Earth’s gravitational field is a basic physical field, generated by the material properties of the Earth System, is an important object of study and methods of geodetic, geophysical, geological, seismic and marine science and other disciplines. In the regions which lack of ground truth space gravity data, the Earth’s gravity model data is the common resource used for geosciences research. The determination of the Earth’s gravity field is an expression of the disturbing potential or its functional mathematical model which is obtained by solving some form of geodetic boundary value problem, including two varieties:the analytical expression model and the numerical model. Analytical expression model utilizes integral expression given by Stokes formula or Molodensky series, and also use the spectral expansion generated from the spherical harmonics. Numerical model is grid values of the gravity field parameters in variety resolution, including the disturbing potential, geoids, gravity anomalies and deflections of the vertical. Using GPS technology, leveling technology and ultra-modern high-end model of the Earth’s gravity field to determine the theory and methods, to find the most applicable in a certain area of the Earth’s gravity field model has important scientific significance.In the beginning, this thesis briefly describes the EGM96and the EGM2008Earth gravity field model; overview of the applicability of analysis of the Earth’s gravity field model commonly used method, and has some of the research results; combined with the purpose of this study and research contents.Subsequently, the theory and the method of determination of the Earth’s gravity field are described, as well as the study background. The theory of Molodensky boundary value problem is particularly explained as an integral foundation of EGM96and EGM2008. This part offers a theoretical basis for the subsequent analysis.Thirdly, through detailed analyze and compare commonly used analysis method to identify defects of the existing research on the application of these methods, meanwhile, combine model of the Earth’s gravitational field theory, a new way to gain height anomaly is proposed. Then in the discussion on the basis of existing analytical methods for the actual implementation of the measured data acquisition mode, GPS level elevation outliers and model elevation anomaly than on the way to the Earth’s gravity field model applicability analysis. Using three sets of data collected in Yunnan region, which show the significant feature of the local topography, verify the usefulness of the method.In the epilogue, the conclusions and recommendations are suggested, as well as propose the recommendations of extension and refinement of applicability analysis of the Earth’s gravity field models. If it can be achieved, we could calculate the normal height by combining the height anomaly which generated from the optimal Earth’s gravity field model with GPS height, and this will bring enormous value in use and economic benefits.