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Based on real BDS-3 ground tracking data in China, it is demonstrated that regional ground stations alone cannot achieve high-precision orbit determination (OD) for BDS-3 IGSO and MEO satellites. Incorporating onboard BDS-3 data from LEO enables high-precision OD for both types, with IGSO satellites showing significant improvement, reaching the same orbit determination accuracy as MEO satellites. A LEO ISL-assisted rapid joint orbit determination method for GNSS and LEO is proposed. Taking advantage of the reduced number of parameters required by LEO ISL data, the method uses a subset of LEO onboard GNSS data, together with regional ground GNSS data and LEO ISLs, to achieve fast full-network orbit determination of large LEO constellations and GNSS. Results show that this method significantly reduces estimation time without sacrificing orbit accuracy of GNSS or LEO.
Integrating LEO onboard BDS-3 data allows GNSS operators to achieve high-precision orbit determination for both IGSO and MEO satellites, enabling more autonomous and reliable constellation maintenance without relying solely on ground stations. The LEO ISL-assisted rapid joint orbit determination method offers a practical solution for fast, full-network OD of large GNSS and LEO constellations, improving operational efficiency while maintaining orbit accuracy. BDS-3 faces challenges in achieving precision orbit determination (POD) due to the difficulty of establishing a globally uniform distribution of independently operated ground tracking stations. The use of onboard BDS-3 observations collected by low Earth orbit (LEO) satellites can partially mitigate this limitation. However, these observations introduce additional parameters, such as receiver clock offsets and carrier-phase ambiguities, which substantially increase the computational burden. Therefore, the capability of achieving real-time (RT) joint POD for BDS-3 and LEO satellites, relying solely on independently operated tracking stations, is greatly constrained. Currently, the inter-satellite links (ISLs) of BDS-3 have been successfully demonstrated to be effective for POD of BDS-3 satellites. In the future, ISLs of LEO satellites will also be incorporated as a measurement technique. Compared to traditional BDS-3 onboard observations, POD using ISLs involves almost no additional parameters other than the orbital states. Therefore, this paper proposes a method that combines onboard BDS-3 receivers on a subset of LEO satellites with LEO ISL observations to achieve rapid high-precision joint POD for BDS-3 and the full LEO constellation. To validate the proposed approach, measured BDS-3 data from regional ground stations in China are employed, together with simulated onboard BDS-3 data and simulated LEO ISL observations. All datasets were obtained over a three-day period, corresponding to days 131–133 of the year 2025. Firstly, it is demonstrated that, when relying solely on regional ground stations, the 24 MEO and 3 IGSO satellites of BDS-3 cannot achieve high-precision POD, with 1D RMS orbit accuracies of only 11.6 cm and 26.9 cm, respectively. Incorporating onboard BDS-3 data from LEO satellites significantly improves orbit determination accuracy, with 1D RMS accuracies reaching 4.9 cm for MEO and 6.4 cm for IGSO satellites, while LEO satellites themselves achieve orbit accuracy better than 5 cm. Subsequently, the computational burden introduced by onboard BDS-3 data from LEO satellites in joint POD is further assessed. On average, incorporating onboard BDS-3 data from 10 LEO satellites adds approximately 6780 parameters to be estimated, substantially increasing computation time. When onboard BDS-3 data from 20 LEO satellites are included, the achieved BDS-3 orbit accuracy shows negligible degradation compared to using data from all LEO satellites, with 1D RMS accuracies of 4.9 cm and 6.7 cm for MEO and IGSO, respectively. Meanwhile, the processing time for a single batch least squares (BLSQ) solution decreases dramatically from 27.0 min to 5.7 min. Increasing the number of LEO satellites to 30 further improves BDS-3 orbit accuracy, mainly due to the enhanced orbit precision of the LEO satellites. After incorporating LEO ISLs, LEO satellites achieve orbit accuracy in the 1D direction of approximately 1 cm, regardless of whether their onboard BDS-3 data are used. In summary, the proposed approach significantly reduces computational burden while ensuring orbit determination accuracy for both BDS-3 and LEO satellites. This approach is more likely to realize real-time joint POD of BDS-3 and LEO satellites based on large-scale LEO constellations.
Details
Simulation;
Orbit determination;
Intersatellite communications;
Ground stations;
Satellite communications;
Real time;
Onboard;
Measurement techniques;
Satellites;
Computer applications;
Satellite constellations;
Earth orbits;
Performance evaluation;
Satellite tracking;
Low earth orbit satellites;
Tracking stations;
Parameters;
Low earth orbits;
Global navigation satellite system
; Huang Guanwen 4 1 College of Geology Engineering and Geomatics, Chang’an University, Xi’an 710054, China, Engineering Research Center of Intelligent BDS, Universities of Shaanxi Province, 126 Yanta Road, Xi’an 710054, China, Shaanxi Yellow River Science Research Institute, 126 Yanta Road, Xi’an 710054, China
2 College of Geology Engineering and Geomatics, Chang’an University, Xi’an 710054, China
3 College of Geology Engineering and Geomatics, Chang’an University, Xi’an 710054, China, Department of Applied Mathematics and Aerospace Engineering, University of Alicante, 03080 Alicante, Spain
4 College of Geology Engineering and Geomatics, Chang’an University, Xi’an 710054, China, Engineering Research Center of Intelligent BDS, Universities of Shaanxi Province, 126 Yanta Road, Xi’an 710054, China