The Vertical Shift between North American Vertical Datum of 1988 and Global Vertical Datum
With the development of space exploration technology,it becomes an effective method to unify global vertical datum by using earth gravity field model.In this paper,the vertical shift between NAVD88 datum and global vertical datum is determined by combining the EGM2008,EIGEN-6C4 ultra-high-degree gravity models and 36 578 GNSS/leveling points in the United States by using the potential difference approach.First,CRUST 1.0,the latest crustal density model,is used to determine the regional crustal density of the United States,which is more realistic to the actual situation than the common assumption of the evenly distributed crustal densities.Then the thresholds are divided according to the distance between GNSS/leveling point and leveling origin.The experi-mental results show that the standard deviation of the vertical shift reached the minimum when the threshold is set at 3 000 km.Finally,the least square method is used to optimize and improve the vertical shift results,and the vertical shift between NAVD88 and global vertical datum is calculated to be －0.956 6 m.
vertical datumCRUST 1.0 modelNorth American Vertical Datum of 1988(NAVD88)vertical shiftGNSS/leveling
万方数据
维普
