Abstract: The Galileo service interruption event in mid July 2019 is a relatively rare major accident in the whole history of satellite navigation development. This paper selects the broadcast ephemeris before and after Galileo service interruption, from two dimensions of vertical (using the data of 29 days before and after interruption) and horizontal (comparing with other major systems), through the four aspects of satellite position, speed, clock difference and SISRE (signal-in-space range error), analyzes the calculation accuracy of broadcast ephemeris before and after interruption. The results show that: from the vertical dimension, before the service interruption, the number of Galileo healthy satellites changes dramatically, the accuracy of satellite clock difference is widely divergent, and the accuracy of satellite position and speed is not significantly abnormal. After the service is restored, all indicators return to normal. From the horizontal dimension, compared with GPS, Galileo system has shown better performance in the accuracy of satellite position, speed and clock. In the field of SISRE, Galileo has obvious advantage with an average SISRE of 0.27 m. GPS and BDS have the comparable orbit accuracy. The average SISRE of GPS is about 0.61 m, and that of BDS MEO, IGSO and GEO is respectively 0.76, 0.58, and 0.68 m. The average SISRE of QZSS (IGSO) and QZSS(GEO) is respectively 0.85 and 0.99 m. GLONASS has slightly poor orbit accuracy, with an average SISRE of 1.05 m.

Key words: Galileo, broadcast ephemeris, signal-in-space range error, satellite position, satellite speed, satellite clock bias