MODELLING LOCAL GPS/LEVELLING GEOID WITH THE ASSESSTMENT OF INVERSE DISTANCE WEIGHTING AND GEOSTATISTICAL KRIGING METHODS

摘要

According to wide spread use of satellite based positioning techniques, especially GPS (Global Positioning System), a greater attention has started to be paid to precise determination of geoid models with an aim to replace the geometric levelling measurements with GPS measurements during geodetic and surveying works. In this paper, geoid modelling is evaluated as a surface fitting problem according to GPS and Levelling data and the main focus is modelling the geoid of a local area as an analytical surface to serve practical geodetic applications such as large scale map production, GIS (Geographical Information Systems) based studies, engineering applications etc. During implementation of the subject, two different interpolation methods, Inverse Distance Weighting (IDW) and Kriging methods are evaluated according to created program routines. In this paper, in addition to compare these two popular interpolation techniques, mainly it is going to emphasize the applicability of interpolation techniques as a tool for modelling the geoid in a local area precisely using GPS/ Levelling data to serve practical applications of geodesy. Also, the importance of precise local geoid models as a part of geodetic infrastructure is underlined with Turkey example.