地球重力场模型在平面控制网中的应用

Application of Gravity Field Model in Horizontal Control Network

现在精密工程测量中GPS与全站仪的共用是普遍存在的事实,这必然存在法线系统与垂线系统的转换问题,以往由于重力场模型精度较低,未能充分顾及到这种差别,而利用现有最新的地球重力场模型,能较精确地计算垂线偏差并将其应用于精密工程测量。本文提出了顾及垂线偏差的GPS与全站仪的精密数据处理方法,通过"三差改正"将全站仪观测值转化为法线系统下的观测值,与GPS数据统一处理,利用某隧道算例验证了地球重力场模型对平面控制网数据处理的影响不容忽视。

It is common to use both of GPS and total station in current precise engineering survey, which leads to the transformation problem between normal and vertical system. Because of the low precision of gravity model in the past, the effect of the problem is ignored. But now, with the latest available gravity field model, it is possible to calculate the verti- cal deflection and apply it to precise engineering survey. According to the characteristic of precise engineering survey, the thesis proposes the precise GPS and total station data processing method taking the vertical deflection into account. The method first transform the total station observation data from normal to vertical system and then process data together with GPS data. According the actual tunnel project example, the result shows that the effect of the earth gravity model on plane control network can not be ignored.