Real-time kinematic positioning of LEO satellites using a single-frequency GPS receiver

摘要

Due to their low cost and low power consumption, single-frequency GPSreceivers are considered suitable for low-cost space applications such as smallsatellite missions. Recently, requirements have emerged for real-time accurateorbit determination at sub-meter level in order to carry out onboard geocodingof high-resolution imagery, open-loop operation of altimeters and radiooccultation. This study proposes an improved real-time kinematic positioningmethod for LEO satellites using single-frequency receivers. The C/A code and L1phase are combined to eliminate ionospheric effects. The epoch-differencedcarrier phase measurements are utilized to acquire receiver position changeswhich are further used to smooth the absolute positions. A kinematic Kalmanfilter is developed to implement kinematic orbit determination. Actual flightdata from China small satellite SJ-9A are used to test the navigationperformance. Results show that the proposed method outperforms traditionalkinematic positioning method in terms of accuracy. A 3D position accuracy of0.72 m and 0.79 m has been achieved using the predicted portion of IGSultra-rapid products and broadcast ephemerides, respectively.