A research of consistencies and progresses of geoid models in Turkey

A number of geoids with various data and names have been determined up to present day in Turkey. In this paper, all Turkish geoids have been reviewed. For this purpose, ten local geoid models have been examined. These are 1976 Turkish Geoid (TG-76), Turkish Geoid-1991 (TG-91), Turkish Doppler Geoid-1992 (TDG-92), Turkish PseudoWGS84Doppler Geoid-1992 (TPDG-92), Turkish Astrogeodetic Geoid-1994 (TAG-94), Turkish GPS/Leveling Geoid, Updated Turkish Geoid-1999 (TG-99A), Turkish Geoid-2003 (TG-03), Turkish Geoid-2009 (TG-09), and Turkish Hybrid Geoid-2009 (THG-09). Within the numerical applications carried out, 30 test benchmarks of the Turkish National Fundamental GPS Network have been selected and geoid heights from each geoid model over these points have been calculated. Later, all of the models have been compared with each other in terms of the criteria based on their developments and geoid height differences have been calculated using local models at the test points. Through these comparisons, the causes of the inconsistencies between the various geoid models are explored while their overall accuracy is determined as well.