Analysis and Monitoring of Groundtrack Drift for Recursive LEO Satellites

Continuous monitoring of the sub-satellite point (SSP) ground track drift of land observation satellites provides an important reference for orbit control, ensuring satellite functionality, and optimizing imaging tasks. This study focuses on analyzing and monitoring the SSP ground track drift for recursive Low Earth Orbit (LEO) satellites, which travel in a predictable, recurring pattern. It also identifies the primary cause of subsatellite point track drift. It further explores its impact on the decay of the semi-major axis and orbital period. Additionally, the study examines how changes in the semi-major axis influence satellite ground track drift, from which the control law for track drift is derived. An accurate orbit prediction model is developed based on osculating Kepler elements. Utilizing the orbit prediction results, the satellite's regression pattern, combined with the subsatellite point longitude at the equator, is employed to match the satellite's regression dates with the reference longitude of the subsatellite point. Consequently, the satellite orbit drift distance is calculated on a daily basis. Using the ZY-3 03 satellite as a case study, orbit prediction is performed, the sub-satellite point track drift distance is calculated, and the track drift pattern is analyzed. The results indicate that the aforementioned method can efficiently achieve long-term monitoring of sub-satellite point track drift and orbit maintenance for LEO satellites with regressive orbits, providing accurate monitoring results. This research provides a technical reference for addressing orbit control challenges related to maintaining sub-satellite point track stability for LEO satellites with regressive orbits.