BDS Broadcast Ephemeris Fitting Based on Satellite’s Position and Velocity

Abstract:

A new fitting method based on both the position and the velocity of satellite is presented in this paper and a fitting formula is deduced. Then, the fitting and the extrapolating accuracy are compared between conventional position based fitting method and the new positionvelocity based fitting method. Compared with conventional fitting method, the new fitting method shows a significant improvement in velocity accuracy, with a slight improvement in position accuracy. Besides, the new method’s advantage is more obvious when the fitting epoch is few.

Key words:BeiDou Navigation Satellite System (BDS); broadcast ephemeris; satellite orbit element; least square fitting; satellite velocity; satellite’s orbit accuracy