Real-Time LEO Satellite Kinematic Orbit Determination Using Code-Carrier Smoothing: Performance Assessment with Sentinel 6A

Hyung-Seok Lee*, Kwan-Dong Park

In real-time kinematic orbit determination (OD) for Low Earth Orbit (LEO) satellites, the dual-frequency Ionosphere-Free (IF) combination reduces ionospheric delay but amplifies code pseudorange noise, limiting accuracy. To address this, Standard Point Positioning (SPP)-based kinematic OD was performed using code-carrier smoothing. Satellite position, velocity, and clock errors were estimated via Least Squares Estimation (LSE) using Global Navigation Satellite System (GNSS) onboard observations from Sentinel-6A, with IF combinations formed from GPS L1/L2 and Galileo E1/E5 signals. A Hatch filter with a smoothing constant of 16 was applied to mitigate high-frequency noise. RINEX and SP3 data were collected at 10-second intervals over 24 hours starting April 20, 2025, from CDDIS and ESA archives, and broadcast ephemerides were used for real-time processing. Compared to SP3 precise orbits, the RMSE without smoothing was 59.5 cm (Radial), 27.9 cm (Along), 22.9 cm (Cross), and 69.6 cm (3D), which improved to 50.0 cm, 23.1 cm, 18.1 cm, and 58.0 cm with smoothing—corresponding to accuracy improvements of 16.0%, 17.2%, 21.0%, and 16.7%, respectively.

Keywords: LEO, kinematic orbit determination, pseudorange, code-carrier smoothing

Speaker 이형석* 인하대학교