Research on application of GPS elevation fitting in existing orbital elevation survey

The application real time kinematic technology is significant for improving the efficiency of the existing track survey. At present, in view of the low efficiency of traditional leveling and the fact that GPS-RTK can not replace traditional leveling methods due to elevation error,a method of plane fitting and quadric surface fitting is proposed to study the accuracy of elevation fitting under different interval control points. Therefore, the real-time kinematic (RTK) and leveling elevation data of inner and outer rails in the same position series are obtained at the test site, and the feasibility and processing method of GPS elevation measurement data based on RTK are analyzed. The results show that,under the condition of introducing a certain control point, the GPS elevation data obtained by using quadric surface fitting can meet the requirements of the existing cable survey within the 500 m interval.