Development of Orthometric Height Acheivement's System using Precise Geoid Model in GP S Surveying

Nowadays, the application field of GPS has been increased and also, this study is based on application of GPS. The purpose of this study is to achieve the orthometric height at GPS surveying point and it can be using the ellipsoidal heights and geoidal heights if we have reliable precise geoid model, So, KOGD2003 precise geoid model was made in and around Korean peninsula by combination of geometric geoid by Gps/leveling data and KOGD2002 which was gravimetric geoid model by remove and restore technique. Then, what so called GPS-GeoL v.1., orthometric height achievement's program was made on the base of KOGD2003 by the visual C++. For the accuracy evaluation of this system, GPS surveying accomplished through Korean second leveling line in Chollabukdo area. The results shows that mean value of the differences between output of this system and official orthometric height of NGII is 0.0089m and RMS of the differences is 0.0332m. Therefore, we can judge that it is possible enough to use this GPS-GeoL v.1.0 program in construction field.