13. Accuracy of the levelling routes

Abstract

The accuracy of levelling routes was determined based on GNSS/levelling data and the Earth gravity model EGM2008 without surveying. From the accuracy of defined levelling routes, managers and surveyors can predict the accuracy of height points which connect to GNSS/levelling points. Therefore, a reasonable plan will be proposed when implementing the work in order to meet both technical and economic aspects. The total of 1804 levelling routes connecting GNSS points/levelling in Northwest, Northeast, Red River Delta, North Central, South Central, Central Highlands, Southeast and Southwest Vietnam were determined. The highest accuracy of levelling route achieved in this study was national grade III. The number of unsatisfactory levelling routes accounts for about 8 % of the total number of routes. The process for determining the accuracy of levelling routes can be applied to other study areas where GNSS/levelling data are available.