GPS高程转换模型在南水北调中线工程中的应用

针对南水北调中线工程线路长、地势较平坦的特点,提出利用GPS高程转换代替水准测量获取正常高的方法.进行GPS高程转换可采用EGM2008模型、GPS高程拟合等方法,根据内、外符合精度公式计算在公共点数目不同情况下的转换精度,并对高程转换精度进行对比.结合南水北调中线工程实例,得出采用EGM2008模型获取正常高为最优的GPS高程转换方法,该方法获取正常高的精度达到四等水准测量要求,可以代替普通水准测量,实现了南水北调中线工程平面和高程控制测量工作的一体化.

Application of GPS Elevation Transformation Model in the Middle Route Project of South-to-North Water Diversion

The Middle Route Project of South-to-North Water Diversion is characterized by long route and fiat terrain, in view of this, a method of calculating the normal height by using GPS elevation transformation instead of leveling is presented. GPS elevation transfor- mation can adopt EGM2008 model and GPS elevation fitting. The transformation precisions are calculated by the precisiori formula un-der the condition of different common point number, and compared between the two transformation models. Combined with the Middle Route Project of South-to-North Water Diversion, EGM2008 model is verified the optimal method for GPS elevation transformation and can meet the demands of fourth-grade-leveling. The method can take the place of the leveling and realized integration of vertical control survey and horizontal control survey in the Middle Route Project of South-to-North Water Diversion.