Daily variation in Asia TWSTFT resulting from satellite motion

Based on the satellite motion, two aspects result in diurnal variations in two-way satellite time and frequency transfer (TWSTFT). One is that since the two distances from two stations to the satellite are different, the satellite receives the two signals at different position. Another is that due to the Sagnac effect, diurnal variations in TWSTFT are also produced. It is concluded that the satellite motion can bring the diurnal variations with the amplitude of several tens ps. And the variation primarily results from the satellite longitude and altitude.