연안해역 수로측량을 위한 수직기준 변환모델링 기술 개발

Abstract

The height datum of Korea is currently separated into land and sea, which makes it difficult to acquire homogeneous and accurate height information throughout the whole nation. In this study, we therefore tried to suggest the more effective way to transform the height information that can be constructed separately according to each height datum on land and sea to those on the unique height datum using precise geoid models and tidal observations in Korea. For this, a precise gravimetric geoid model was firstly developed using the remove and restore (R-R) technique with all available gravity observations. The gravimetric geoid model were then fitted to the geometric geoidal heights, each of which were represented as height datum of land or sea respectively, obtained from GNSS/Levelling results on 330 TBMs in the study area. Finally, we determined the differences between the two hybrid geoid models to apply the height transformation between IMSL and LMSL. The co-tidal chart model of TideBed system developed by Korea Hydrographic and Oceanographic Agency (KHOA) which was re-gridded to have the same grid size and coverage as the geoid model, so that this can be used for the height datum transformation from LMSL to local AHHW and/or from LMSL to local DL. The accuracy of height datum transformation based on the workflow suggested in this study was approximately ±5 cm. As a result of this study, various height measurement available can be converted to the IMSL. Thus, it can be helpful to minimize the confusions on the use of geo-spatial information due to the disagreement caused by different height datum around land and sea in Korea, and also it will be very economic and time saving for the coastal development and disaster prevention projects in the future.