LEO Satellite Clock Modeling and Its Benefits for LEO Kinematic POD

High-accuracy Low Earth Orbit (LEO) satellite clock and orbital products are preconditions to realize LEO augmentation for high-accuracy GNSS-based positioning on the ground. There is a high correlation between orbit parameters in kinematic Precise Determination (POD) process. While future satellites planned be equipped with better clocks, benefits of modeling high-stability clocks not yet thoroughly investigated, particularly when mid- long-term systematic effects induced by complex relativistic external environment remain clocks. Through modeling, this study attempts reduce only short-term noise radial orbits, but also mis-modeled caused by, e.g., real-time GNSS errors. To explore need first detrended effects. over-detrending limits improvements, weak detrending would hamper strong easily lead performance degradations. A balance strengths model thus needs investigated different types. In study, Piece-Wise Linear (PWL) time lengths 2.5-state filter (h values) tested using real data from GRACE FO-1 an Ultra-Stable Oscillator (USO) board. Using CNES GPS products, it was found that smoothing window 300 500 s, one could generally expect improvement larger than 10% estimation orbits applying PWL length 1200 s. Improvements size can expected h−1 (for Flicker Frequency Noise) 10−28 10−30.