New Satellite Orbit Determination Method Enhances Navigation Precision for Mega-Constellations

Researchers from Wuhan University have introduced a novel rotation-corrected precise orbit determination (POD) method that promises to revolutionize navigation precision for future satellite mega-constellations. This innovative approach integrates inter-satellite link (ISL) data with onboard BeiDou-3 (BDS-3) observations to simultaneously determine the orbits of both Low Earth Orbit (LEO) and BDS-3 Medium Earth Orbit (MEO) satellites, addressing the critical issue of systematic constellation rotation.

The significance of this development cannot be overstated, as it offers a solution to one of the most persistent challenges in autonomous constellation orbit determination—systematic rotation caused by the lack of an absolute spatial reference. By leveraging BDS-3 broadcast ephemerides and applying a rotation correction, the method has demonstrated the ability to reduce LEO orbit errors from over 20 cm to about 1 cm. This achievement is particularly relevant for modern satellite constellations like OneWeb, Starlink, and CENTISPACETM, which aim to provide global communications and navigation services but face limitations due to the high costs and geopolitical constraints associated with dense ground station networks.

Published in Satellite Navigation, the study showcases the method's effectiveness through simulations involving a 66-satellite LEO constellation equipped with ISLs and onboard BDS-3 receivers, alongside 24 real BDS-3 MEO satellites. The results indicate a dramatic improvement in orbit accuracy, with LEO along-track and cross-track errors dropping to 1.3 cm and 4.2 cm, respectively, and MEO errors falling to about 13 cm. This advancement not only enhances the reliability and accuracy of satellite navigation services but also reduces operational costs and hardware requirements, making it a scalable solution for real-time applications in large-scale LEO constellations.

Dr. Kecai Jiang, the corresponding author of the study, highlights the method's efficiency and scalability, emphasizing its potential to support a wide range of applications, from global navigation augmentation to precision agriculture and disaster response. By minimizing dependence on ground infrastructure, this innovation paves the way for resilient operations in remote or geopolitically constrained regions, marking a significant step forward in the integration of LEO constellations with existing GNSS systems to enhance global navigation and timing performance.