Sagnac effect on two-way satellite time and frequency transfer

Combined with two-way satellite time and frequency transfer (TWSTFT), a Sagnac effect solution about satellite motion is proposed. The TWSTFT technique is based on geostationary satellite. As a result of the perturbation forces, the geostationary satellite is not absolutely stationary, but it does the diurnal motion with small amplitude. Sagnac effect is closely related to both satellite and earth observation station positions. The satellite' motion makes Sagnac effect have diurnal variance characteristic. The Sagnac effect value is calculated by using the high accuracy orbit data of geostationary satellite. It is shown that the Sagnac effect value is variable with variety of satellite positions. The variety value is about several hundred picoseconds. It improves the Sagnac effect correction accuracy comparing with the conventional method assuming that the geostationary satellite is absolutely stationary. It has the important application value for all kinds of time transfer methods and satellite navigation community.