Breakthrough hybrid model restores orbit accuracy for BeiDou-3 satellites

Breakthrough hybrid model restores orbit accuracy for BeiDou-3 satellites
by Riko Seibo
Tokyo, Japan (SPX) Jun 12, 2025

Two BeiDou-3 navigation satellites once plagued by orbit inconsistencies are now operating with significantly improved accuracy, thanks to a novel hybrid modeling technique that better accounts for solar radiation pressure. Researchers integrated a physically based Adjustable Box-Wing (ABW) model with the empirical ECOM2 framework, cutting laser ranging residuals by over 60% and improving real-time orbit prediction reliability.

The anomalies emerged after some BeiDou-3 satellites, including C223 and C222, were equipped with Medium Earth Orbit Search and Rescue (MEOSAR) payloads. These additions disrupted satellite symmetry and created modeling challenges for solar radiation pressure (SRP), which standard models like ECOM2 failed to address effectively. With precise orbit prediction vital for applications such as navigation and Earth monitoring, researchers sought a more robust solution.

A team from Chang'an University presented their findings in a study published June 2, 2025, in Satellite Navigation. Their work introduces a hybrid model combining ABW and ECOM2 methods to reflect how sunlight interacts with satellites equipped with asymmetric MEOSAR payloads. The researchers developed two ABW variants (ABWX and ABWMX), depending on the payload's orientation (+X or -X side), and tested them against traditional methods.

The study further proposed four hybrid strategies (S1-S4) that blend the ABW-derived solar force estimations into the ECOM2 model. These strategies reduced residual standard deviations from 7.8 cm to 3 cm and enhanced both orbit boundary continuity and short-term prediction accuracy. The configuration assuming the payload is mounted on the +X side delivered the best performance. To ease operational integration, the team created a priori SRP models using Fourier-transformed ABW data, enabling corrections without increasing computational load.

"This study resolves a long-standing problem in satellite orbit modeling," said Prof. Guanwen Huang, corresponding author. "By identifying the root cause of the anomalies and developing a strategy that updates with each orbit arc, we've significantly enhanced the reliability of BeiDou-3. Our approach doesn't just improve one or two satellites-it sets a precedent for how we model satellites with complex or asymmetric payloads going forward."

The modeling approach holds promise beyond BeiDou-3. Its adaptability and precision make it a compelling option for future Global Navigation Satellite Systems (GNSS) enhancements, including Galileo and GPS updates. By offering both physical fidelity and real-time feasibility, the strategy marks a significant advancement for satellite navigation infrastructure.

Research Report:Study of the SRP model for BDS-3 satellites SVN C223 and C222 to mitigate SLR residual anomalies