Investigation on Geoid Modeling Techniques and Height Systems
The basic objective of the project is developing a high accuracy local geoid model using hybrid data set and validations with independent terrestrial data and geostatistical method.
Today, satellite based positioning systems (GNSS) comes in front of the positioning techniques in many geodetic and surveying applications. The fact that the 3D position accuracy, obtained with satellite based techniques is in the centimeter level or even better. Use of GNSS positioning with high-accuracy regional geoid model gives opportunity to transform the GPS-ellipsoidal heights into orthometric heights in local vertical datum as well. In addition, the accuracies in geoid modeling improves significantly with progressing gravity field data acquisition technologies and new methodological contributions. Regarding with the examples from various countries, a 1-2 cm accuracy in geoid models is possible. Different geoid models have been calculated since 1970’s in Turkey. The accuracy of current regional geoid model in Turkey is reported to be approximately 8 cm. However, in practice, this accuracy does not meet the requirement for height conversion. The studies for improvement of Turkey regional geoid model accuracy are going on under Turkey National Height System modernization. Until having a geoid model with few centimeter accuracy, local geoid models provides solution to height transformation in geodetic applications in Turkey.