The Study Of The Method For Height Datum Unification In Asia-Pacific Region Based On GOCE Gravity Field Models

A unified height datum plays an important role in the construction of modern surveying and mapping system,the engineering construction,national defense and global monitoring and other fields.With the development of global navigation satellite system,satellite altimetry and other space geodetic techniques and the success of GRACE,GOCE satellite gravity mission,the establishment of a unified global height datum has become possible.Therefore,it has theoretical and practical significance for research in the vertical datum unification of China and neighboring countries.Height datum unification is realized by determining the geopotential differences or vertical differences between the local and the global height datum.According to the vertical deviation of height datum between different countries and regions in Asia-Pacific region,after analyzing the method of height datum unification and global gravity field models,the offset between height datum of different countries and regions in Asia-Pacific region and global height datum were calculated using the method of GPS/levelling combined GOCE based gravity field model and the method of ocean levelling,concerning the information of available data.The main work is:A brief introduction to the concept of height datum and the method for mean sea level monitoring using tide gauge and satellite altimetry was given.The advantage and disadvantage of the methods for height datum unification,such as geometric levelling combined gravimetry,geodetic boundary value problem approach,GPS/levelling combined gravity field model and ocean levelling were discussed.The performance of gravity field model in height datum unification was analyzed using GPS/levelling data in Europe.Then the definition of national height datum and the method of determining geopotential of starting plane in Asia-Pacific region was introduced,and the vertical deviation between mean sea level at tide gauge station and national height datum in Asia-Pacific region and global height datum was calculated using GPS/levelling data combined EGM2008,EIGEN-6C4,GECO and other global gravity field model and DTU10 mean dynamic topography model.