Abstract: The International GNSS Service Center only provides the precision ephemeris data from 00:00:00 to 23:45:00 on the same day. To obtain the complete ephemeris data on the same day, the ephemeris data of 23:45:00—24:00:00 period is often obtained by the method of coordinate extrapolation. In this paper, we use trigonometric interpolation and generalized extended approximation to extrapolate the precise ephemeris orbital coordinates of BeiDou satellites of different types and time intervals for a period of time. The results show that the extrapolation accuracy of the precise ephemeris orbital coordinates of GEO satellites is better than that of IGSO and MEO satellites. The extrapolation accuracy of the two extrapolation methods is significantly higher for the 5 min interval precision ephemeris than for the 15 min interval precision ephemeris, and the extrapolation accuracy of the trigonometric interpolation method is better than that of the generalized extended approximation method with one to two orders of magnitude. Therefore, when extrapolating the orbital coordinates of the precision ephemeris of BeiDou satellites, the trigonometric interpolation method with higher accuracy and the use of ephemeris data with 5 min interval can be preferred for the extrapolation calculation.

Key words: BeiDou satellite precision ephemeris, orbital coordinate extrapolation, trigonometric interpolation, generalized extended approximation method, optimal accuracy analysis