Full Length Research Paper

Evaluation of recent global geopotential models based on GPS/levelling data over Afyonkarahisar (Turkey)

Ibrahim Yılmaz¹*, Mustafa Yılmaz², Mevlüt Güllü¹ and Bayram Turgut¹

¹Department of Geodesy and Photogrammetry, Faculty of Engineering, Kocatepe University of Afyonkarahisar, Ahmet Necdet Sezer Campus Gazlıgöl Yolu 03200, Afyonkarahisar, Turkey.

²Directorship of Afyonkarahisar, Osmangazi Electricity Distribution Inc., Yuzbası Agah Cd. No: 24, 03200, Afyonkarahisar, Turkey.

*Corresponding author. E-mail: iyilmaz@aku.edu.tr.

Accepted 20 January, 2010

   Abstract

This study presents the evaluation of the global geo-potential models EGM96, EIGEN-5C, EGM2008(360) and EGM2008 by comparing model based on geoid heights to the GPS/levelling based on geoid heights over Afyonkarahisar study area in order to find the geopotential model that best fits the study area to be used in a further geoid determination at regional and national scales. The study area consists of 313 control points that belong to the Turkish National Triangulation Network, covering a rough area. The geoid height residuals are investigated by standard deviation value after fitting tilt at discrete points, and height-dependent evaluations have been performed. The evaluation results revealed that EGM2008 fits best to the GPS/levelling based on geoid heights than the other models with significant improvements in the study area.

Key words: Geopotential model, GPS/levelling, geoid height, EGM96, EIGEN-5C, EGM2008(360), EGM2008.