Evaluation of the modern Earth Gravitational Models over territory of the Kyrgyz Republic

Abstract

The results of study of the satellite positioning technologies to determine normal heights in the Kyrgyz Republic based on modern digital Earth Gravitational Models are presented. The performances of the EGM96 and EGM2008 models, over territory of the Kyrgyz Republic, have been evaluated in the local conditions. Results of the study show how varies the height differences between the surfaces of the gravity model EGM2008 and Baltic Height System-1977 based on satellite observations at 65 geodetic points of the National “Kyrg-06” reference frame network in 2005-2006. The arithmetic mean of the height differences and the standard deviation are 0.394 m and 0.819 m, respectively. Calculation of height differences between the surfaces of the gravity models EGM96, EGM2008 and BHS-1977 system shows that EGM2008 has a higher accuracy. On the territory of the Kyrgyz Republic, all measured points have a negative height difference with a standard deviation of 0.413 m, which also shows the possibility of using the EGM2008 as a basic model when developing a local geoid model in the Kyrgyz Republic. The local performance of EGM96 and EGM2008 has been evaluated for the territory of Bishkek city. A local geodetic network, based on the National Geodetic Network points, is established and GNSS observed within this research work.