EGM2008重力场模型在南水北调中线工程中的应用

Application of EGM2008 model in the middle route of South-to-North Water Transfer Project

针对南水北调中线工程具有线路长、地势较平坦的特点,提出利用EGM2008地球重力场模型的方法。以水准测量成果为真实值,计算高程拟合内外符合精度及每公里高差中误差,评定EGM2008模型与平面拟合方法的高程拟合精度。结合南水北调中线工程实例表明,EGM2008模型获取正常高结果可以达到四等水准测量要求,且拟合精度优于平面拟合精度。因此,EGM2008地球重力场模型在高程测量中的应用,有助于实现南水北调中线工程中平面和高程控制测量的一体化。

In terms of the characteristics of long route and smooth terrain of the Middle Route of the South-to-North Water Transfer Project, this paper proposed a method to calculate the height anomaly and obtain the normal height using the EGM2008 model. The leveling results were considered as the true values, the elevation fitting precision and error in the elevation difference per kilometer were calculated, and the height fitting precision based on the EGM2008 model and plane fitting method was evaluated. According to the engineering example, it showed that the normal height results obtaining from the EGM2008 model can meet the demand of fourth-grade-leveling and the fitting precision is better than that obtained from the plane fitting method. Thus, EGM2008 model can realize the integration of horizontal and vertical control survey in the Middle Route of the South-to-North Water Transfer Project.