Data processing and error analysis of two way satellite time and frequency transfer

Two way satellite time and frequency transfer (TWSTFT) is the most precise remote time transfer method. The comparison precision of TWSTFT could approximately reach 0.3ns. The basic principle and construction of TWSTFT in National Institute Metrology (NIM) were demonstrated. When the data was processing, software standardization guide made by Consultative Committee for Time and Frequency (CCTF) was adopted and the comparison precision of NIM is about 0.35ns. According to the TWSTFT schematic diagram of transfer path, equipment delay, ionosphere refraction and satellite motion relative to ground station are the main error sources to the comparison precision. The results show that the equipment delay error is the major source in the TWSTFT with the value of 0.12ns.