Precise Orbit and Clock Offset Determination of LEO Navigation Satellites Based on Multi-constellation and Multi-frequency Spaceborne GNSS Data

With massive low earth orbit (LEO) satellites, LEO navigation enhancement system is important to improve the service performance of GNSS system. The high precision orbit and clock offset calculation of LEO satellites is one key to establish the stable and reliable space-time reference. Based on GPS/BDS/GALILEO data measured by LEO navigation satellites, this paper determines the precise LEO orbit and clock offset, and evaluates the precision of LEO orbit and clock offset solution. The orbit determination accuracy using GPS (L1/L2), GPS (L1/L5), BDS (B1C/B2a), and GALILEO (E1/E5a) combination is 2.42, 2.93, 2.67, and 2.87 cm, respectively. The clock offset solution accuracy using the above four combination is 0.167, 0.194, 0.186, and 0.180 ns, respectively. These results can provide high-quality product for navigation enhancement system services.