Research on Interpolation Accuracy of Precise Ephemeris of Beidou Satellite

The non-sliding Lagrange interpolation method and sliding Lagrange interpolation method are used to interpolate the precise ephemeris of Beidou satellite navigation system (BDS). The relationship between interpolation accuracy and interpolation order of BDS satellite and two methods is studied. The results show that when non-sliding and sliding Lagrange interpolation are used respectively the interpolation errors of MEO and IGSO satellites are approximately U-shaped and L-shaped with the increase of the order, while the interpolation errors of GEO satellites increase gradually and are approximately stable with the increase of the order. When the interpolation order is low, the interpolation errors of the two methods have certain regularity, but the regularity of GEO satellite interpolation error is weaker than that of MEO satellite and IGSO satellite. The difference of the optimal interpolation order of the two methods for each satellite is within 1, and under the best interpolation order the accuracy of sliding Lagrange interpolation is 11.96%~44.01% higher than that of non-sliding interpolation, and the interpolation accuracy of GEO satellite is better than that of MEO satellite and IGSO satellite.