Fig. 1. Atmospheric dispersion in satellite-to-earth unidirectional time transfer mode. (a) Geometry of atmospheric dispersion; (b) geometric models of atmospheric dispersion

Fig. 2. Scene of satellite-to-earth unidirectional time transfer by multiple satellites

Fig. 3. Variation of satellite-to-earth unidirectional time transfer deviation by single satellite (user's position is known, laser wavelength is 815 nm). (a) Time transfer deviation of different sites in each month when zenith angle is 60°; (b) variation of time transfer deviation in different sites with zenith angle in January

Fig. 4. Variation of satellite-to-earth unidirectional time transfer deviation by single satellite (user's position is known, laser wavelength is 1550 nm). (a) Time transfer deviation of different sites in each month when zenith angle is 60°; (b) variation of time transfer deviation in different sites with zenith angle in January

Fig. 5. Variation of satellite-to-earth unidirectional time transfer deviation by four satellites(user's position is unknown, laser wavelength is 815 nm). (a) Variation of time transfer deviation in different sites with zenith angle in January; (b) maximum time transfer deviation of different sites in each month when zenith angle is 60°

Fig. 6. Variation of satellite-to-earth unidirectional time transfer deviation by four satellites (user's position is unknown, laser wavelength is 1550 nm). (a) Variation of time transfer deviation in different sites with zenith angle in January; (b) maximum time transfer deviation of different sites in each month when zenith angle is 60°

Fig. 7. Annual maximum unidirectional time transfer deviation of different sites (zenith angle is 60°)