Unlocking the future of satellite navigation with smart techniques

Tracking the orbits of extensive LEO satellite networks presents considerable challenges due to their sheer numbers and the demand for continuous, high-precision data. While ground-based tracking stations struggle to keep up, spaceborne GNSS receivers offer an alternative. However, existing methods face limitations in computational efficiency and precision, necessitating innovative approaches.

A study published on February 10, 2025, in *Satellite Navigation* (DOI: 10.1186/s43020-025-00160-1) by the Xi'an Research Institute of Surveying and Mapping and the State Key Laboratory of Spatial Datum introduces stepwise autonomous OD techniques for large LEO constellations. By integrating GNSS data with inter-satellite ranging, the research enhances both the precision and computational feasibility of orbit tracking.

Three novel OD strategies were proposed. The first method fuses GNSS data with inter-satellite link (ISL) range measurements to refine orbit parameters. The second employs ISL ranges as constraints to improve accuracy without additional computational demand. The third technique dynamically adjusts the covariance matrix of orbit predictions to correct for errors introduced by anomalies in the dynamic model. Initially, orbit parameters are estimated using GNSS data, followed by refinements based on ISL range measurements. The adaptive method stands out by modifying the covariance matrix with an adaptive factor that controls dynamic model discrepancies. Simulations indicate notable improvements, with root mean square errors (RMSE) of position estimates reaching as low as 11.34 cm when combining dynamic models with ISL ranges. Additionally, parallelization of estimation processes for individual satellites minimizes computational load, enabling scalable solutions for vast satellite networks.

Dr. Yuanxi Yang, a prominent expert in satellite navigation and a study co-author, emphasized the significance of these findings: "Our stepwise autonomous OD methods provide a practical solution to the computational and accuracy challenges faced by large LEO constellations. By integrating GNSS observations and ISL ranging, we achieve higher precision and efficiency, paving the way for more robust satellite operations."

The impact of this research extends across multiple domains. Enhanced OD methods offer scalable solutions for managing large LEO constellations, ensuring improved satellite communication, remote sensing, and navigation augmentation. As these constellations expand in scale and complexity, the proposed techniques provide a dependable framework for maintaining precise orbit control, unlocking vast potential in global navigation, environmental monitoring, and beyond.

Research Report:Stepwise autonomous orbit determination of large LEO constellations by GNSS observations with partial inter-satellite ranging