COMPARISON OF ELEVATION MEASUREMENTS BETWEEN GNSS AND LEVELING METHODALONG YOM RIVER PHRAE PROVINCE

Abstract

According to the Development of Precise Geoid Model of Thailand, elevations of objects or ground points are determined by GNSS network method instead of conventional leveling. Six permanent monuments are constructed on bridges and on ground along Yom river Mueang District Phrae Province for this project. Measuring geographic coordinates of monuments by static method, observing simultaneously at least 1 hours (by technique of relative positioning). Compute geoid undulation from TGM2017 and compute elevations by GNSS method. Measuring elevations of monuments by the method of closed circuit differential leveling by digital level. After comparing elevations by both method. The RMSE of elevations by GNSS method is equal to 0.027 meter or better than 12mm√Kor Order 3 (leveling). Elevations by GNSS method is better than leveling method for this project area.