Evaluation of global and regional geoid models in South Korea by using terrestrial and GNSS data

In this study, 96 bench marks and unified control points across South Korea were selected as GPS/Leveling stations, GPS surveying was conducted in the Network-RTK (VRS) method and the results were utilized to calculate geometric geoidal heights. These geometric geoidal heights were utilized in the evaluation of the geoid models comprising global gravity field models, such as EGM2008 and EIGEN-6C4, and South Korean geoid models, such as KNGoeid13 and KNGeoid14. In addition, geoid model KNGeoid14, which was found to have the highest accuracy and precision through the evaluation, was utilized to calculate GPS derived orthometric heights, and the results were evaluated to review the possibility of orthometric height surveys using the GPS/Geoid method. As for the results of the study, in the evaluation of the global gravity field models, the standard deviations of EGM2008 and EIGEN-6C4 were shown to be almost the same as the values were 7.0 cm and 7.1 cm respectively, and geoid model KNGeoid14 was found to have been improved compared to KNGeoid13 as its RMS and standard deviation were shown to be smaller than those of KNGeoid13. In addition, differences in the orthometric height values of 96 points derived in the GPS/Geoid method were analysed using geoid model KNGeoid14, and, in the results, the average error was shown to be 3.9 cm and the standard deviations was shown to be 5.2 cm so that the possibility of utilization of the GPS/Geoid method in orthometric height surveys with the decimeter accuracy could be identified.