Determination of the Geopotential and Orthometric Height Difference Based on the Two Way Satellite Time and Frequency Transfer Observations

According to general relativity theory, the geopotential difference between two positions gives rise to a clock's running rate difference (time difference) or oscillation frequency difference. Inversely, the geopotential difference and height difference between these two positions can be determined by measuring the frequency or time difference between two clocks located at these two positions. Using the TWSTFT, two way satellite time and frequency transfer data sets at five timing-keeping stations released by the BIPM ( Bureau International des Poids et Mesures), we determined the geopotential difference and height difference between any two of the five stations based upon the gravity frequency shift method and TWSTFT technique. Compared with EGM2008 model results, the standard deviations of the geopotential and height differences are 129.2 m²·s^-2and 13.2m, resp-ectively. Our experimental results are consistent with the current stability level 10E-15 of the atomic clocks installed at the time-keeping stations. The quick development of time-frequency science, including highly precise atomic clocks or optical clocks, creates the potential for using the TWSTFT technique to determine geopotential and height difference, as well as enable its extensive application in various fields.