New satellite orbit determination method could boost navigation precision for future mega-constellations

Satellite Orbit Method Promises Centimeter-Level Precision for Future Mega-Constellations

Breakthrough technology from Wuhan University could transform autonomous navigation for thousands of LEO satellites

Chinese researchers have developed a groundbreaking method for determining satellite orbits that could revolutionize the operation of massive low-Earth orbit (LEO) satellite constellations like Starlink, OneWeb, and Amazon's Project Kuiper. The innovation addresses one of the most persistent challenges in autonomous satellite navigation: maintaining precise positioning without relying on extensive ground-based tracking networks.

The Challenge of Mega-Constellation Navigation

Modern satellite constellations are rapidly expanding, with SpaceX's Starlink alone consisting of over 7,600 satellites as of May 2025, comprising 65% of all active satellites. These mega-constellations promise global communications and navigation capabilities, but their precise orbit determination (POD) has traditionally required dense ground station networks that are costly and often limited by geopolitical constraints.

The fundamental problem lies in what researchers call "rotational unobservability" – when satellites rely solely on inter-satellite links (ISLs) for navigation, the entire constellation can drift in orientation due to the lack of an absolute spatial reference point. This systematic rotation can cause orbit errors of up to 40 cm cross-track error for LEOs and over 1 meter for medium-Earth orbit satellites.

The Wuhan University Breakthrough

Researchers at Wuhan University have developed a rotation-corrected integrated POD method that addresses this critical limitation. Published in Satellite Navigation on August 4, 2025, the study demonstrates how the technique simultaneously estimates the orbits of Low Earth Orbit (LEO) and BDS-3 Medium Earth Orbit (MEO) satellites, corrects systematic rotation using BDS-3 broadcast ephemerides, and achieves centimeter-level precision.

The method works by fusing inter-satellite link measurements with onboard BeiDou-3 (BDS-3) GNSS observations. By referencing the coordinate system embedded in BDS-3 broadcast ephemerides and applying corrective rotations, the system can maintain accurate positioning without ground-based infrastructure.

Remarkable Performance Results

The testing results demonstrate the transformative potential of this approach. In simulations involving a 66-satellite LEO constellation equipped with ISLs and onboard BDS-3 receivers alongside 24 real BDS-3 satellites, LEO orbit errors were reduced from more than 20 cm to around 1 cm, enabling high-accuracy, low-latency solutions without dependence on dense global ground station networks.

Specifically, after correction, LEO along-track and cross-track errors dropped from 22.7 cm and 39.3 cm to 1.3 cm and 4.2 cm, respectively. Even more impressive, MEO errors fell from over 1.2 m to about 13 cm.

The system maintains its effectiveness even with partial GNSS coverage. When only 36 of 66 LEOs carried GNSS receivers, ISL connectivity propagated the correction across the constellation with minimal accuracy loss.

Current Mega-Constellation Landscape

This breakthrough comes at a critical time for the satellite industry. Eutelsat's LEO revenue was up 84.1 percent to €186.8 million in fiscal 2025, while the company has ordered an initial batch of 100 additional satellites in December 2024, as well as the procurement of 340 further satellites for the current LEO constellation.

Amazon's Project Kuiper is also ramping up operations, with more than 3,000 satellites to be manufactured at its 16,000 m² facility over several years, at a peak rate of five satellites per day. The company expects to start offering services to a variety of sectors, including maritime, in 2025.

Meanwhile, OneWeb has faced some operational challenges. On 31 December 2024, the OneWeb constellation had a 48 hour service outage due to ground equipment software maintained by Hughes Network Systems failing to accommodate the extra day of the 2024 leap year, highlighting the importance of robust autonomous systems.

Advanced Research in Satellite Maneuvering

Complementing the orbit determination breakthrough, researchers are also advancing satellite maneuver prediction capabilities. A recent study published in December 2024 demonstrated that deep learning methods can successfully forecast 95.12% of future maneuvers for satellites in their on-station phase and 88.97% for the parking phase.

This research is particularly important given the increasing complexity of managing thousands of maneuvering satellites. As of 28 April 2025, the number of operational Starlink satellites in orbit was reported to be 7239, and these satellites perform frequent maneuvers for collision avoidance and orbit maintenance.

BeiDou-3 System Advances

The success of the new orbit determination method is enabled by advances in China's BeiDou-3 Navigation Satellite System. BDS currently consists of 45 operational satellites in orbit, delivering services through 15 BDS-2 and 30 BDS-3 satellites. Since May 2023, five BDS-3 backup satellites have been launched to bolster system resilience.

China is actively promoting the integrated development and experimental validation of BDS and LEO satellite navigation augmentation systems. Results demonstrate that GNSS orbit determination accuracy is better than 5 cm (1σ), and clock error determination accuracy is superior to 0.15 ns (1σ).

Environmental and Safety Considerations

As mega-constellations continue to expand, researchers are increasingly concerned about space environment impacts. Studies show that satellite re-entries from the Starlink mega-constellation alone could deposit more aluminum into Earth's upper atmosphere than what is done through meteoroids, potentially making them the dominant source of high-altitude alumina.

The new orbit determination method could help address some safety concerns by enabling more precise autonomous operations. SpaceX satellites will maneuver if the probability of collision is greater than 10⁻⁶ (1 in 1,000,000 chance of collision), compared to the industry standard of 10⁻⁴ (1 in 10,000 chance of collision).

Global Market Expansion

The satellite internet market continues to expand globally. South Korea has officially cleared the way for low-earth orbit (LEO) satellite internet services, granting regulatory approval for SpaceX's Starlink and Eutelsat's OneWeb to operate in the country. This approval came in May 2025 and signals the country's entry into the high-stakes race for 6G infrastructure leadership.

The African continent is attracting all the major LEO satellite constellations such as StarLink (US), OneWeb (EU), Amazon Kuipers (US), and Telesat Lightspeed (CAN), though regulatory approval across 54 African nations remains complex and time-consuming.

Future Implications

Dr. Kecai Jiang, the corresponding author of the Wuhan University study, emphasized the method's significance: "This method tackles one of the most stubborn issues in autonomous constellation orbit determination—systematic rotation caused by the lack of absolute spatial reference. By harnessing readily available BDS-3 broadcast ephemerides and inter-satellite measurements, we can deliver centimeter-level precision without waiting for post-processed GNSS products or building extensive ground networks."

The rotation-corrected integrated POD method holds significant promise for global navigation augmentation, autonomous LEO-based navigation systems, and real-time positioning services. By dramatically reducing reliance on ground infrastructure, it enables resilient operations in remote or geopolitically constrained regions.

This innovation could become a cornerstone technology for integrating LEO constellations with existing GNSS systems to enhance global navigation and timing performance. As the satellite industry prepares for the deployment of tens of thousands of additional satellites over the next decade, autonomous, high-precision orbit determination will be essential for safe and efficient operations.

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Sources

1. Cozzens, T. (2025, August 20). New satellite orbit determination method could boost navigation precision for future mega-constellations. GPS World. https://www.gpsworld.com/new-satellite-orbit-determination-method-could-boost-navigation-precision-for-future-mega-constellations/
2. 24-7PressRelease. (2025, August 15). Rotation-corrected satellite precise orbit determination method boosts navigation precision for future mega-constellations. https://www.24-7pressrelease.com/press-release/525867/rotation-corrected-satellite-precise-orbit-determination-method-boosts-navigation-precision-for-future-mega-constellations
3. Newswise. (2025, August 14). Rotation-corrected satellite precise orbit determination method boosts navigation precision for future mega-constellations. https://www.newswise.com/articles/rotation-corrected-satellite-precise-orbit-determination-method-boosts-navigation-precision-for-future-mega-constellations
4. EurekAlert! (2025, August 14). Rotation-corrected satellite precise orbit determination method boosts navigation precision for future mega-constellations. https://www.eurekalert.org/news-releases/1094864
5. TS2.tech. (2025, June 21). Mega-constellations exposed: How swarms of tiny satellites are taking over low Earth orbit. https://ts2.tech/en/mega-constellations-exposed-how-swarms-of-tiny-satellites-are-taking-over-low-earth-orbit/
6. Lawrence, A., et al. (2021, May 20). Satellite mega-constellations create risks in Low Earth Orbit, the atmosphere and on Earth. Scientific Reports. https://www.nature.com/articles/s41598-021-89909-7
7. Chen, L., et al. (2024, December 25). Mega-constellation satellite maneuver forecast via network with attention mechanism. Advances in Space Research. https://www.sciencedirect.com/science/article/abs/pii/S0273117724013048
8. Wang, Z., et al. (2025, July). Orbit determination for continuously maneuvering Starlink satellites based on an unscented batch filtering method. Aerospace, 12(7). https://pmc.ncbi.nlm.nih.gov/articles/PMC12252113/
9. Zhang, Y., et al. (2022). LEO mega constellations: Review of development, impact, surveillance, and governance. Space: Science & Technology. https://spj.science.org/doi/10.34133/2022/9865174
10. Xu, B., et al. (2025, April 10). Robust distributed autonomous orbit determination for LEO mega constellation based on inter-satellite ranging and astronomical measurement. Advances in Space Research. https://www.sciencedirect.com/science/article/abs/pii/S0273117725003473
11. Seibo, R. (2025, August 20). Rotation corrected orbit method promises centimeter level precision for mega constellations. SpaceWar. https://www.spacewar.com/reports/Rotation_corrected_orbit_method_promises_centimeter_level_precision_for_mega_constellations_999.html
12. The Register. (2025, August 5). Eutelsat LEO revenue rockets 84%. https://www.theregister.com/2025/08/05/eutelsat_leo_revenue
13. Wikipedia. (2025). Eutelsat OneWeb. https://en.wikipedia.org/wiki/Eutelsat_OneWeb
14. TechnEconomyBlog. (2024, March 14). The next frontier: LEO satellites for internet services. https://techneconomyblog.com/2024/03/12/the-next-frontier-leo-satellites-for-internet-access/
15. SpaceNews. (2023, February 22). Europe making progress on sovereign LEO constellation as OneWeb and Starlink race ahead. https://spacenews.com/europe-making-progress-on-sovereign-leo-constellation-as-oneweb-and-starlink-race-ahead/
16. Riviera. (2025). Amazon ramps up LEO satellite output ahead of 2025 service launch. https://www.rivieramm.com/news-content-hub/news-content-hub/amazon-ramps-up-leo-satellite-output-ahead-of-2025-service-launch-81417
17. Wikipedia. (2025). Starlink. https://en.wikipedia.org/wiki/Starlink
18. Latest Internet Space. (2025, April 18). Exploring satellite internet: Top Starlink alternatives in 2025. https://lastestinternet.space/satellite-internet-top-starlink-alternatives/
19. KED Global. (2025, May 30). SpaceX's Starlink, Eutelsat's OneWeb land in Korea for LEO satellite services. https://www.kedglobal.com/aerospace-defense/newsView/ked202505300006
20. OceanWeb Ltd. (2024, July 31). The LEO effect: Starlink vs OneWeb. https://www.oceanweb.com/the-leo-effect-starlink-vs-oneweb/
21. Oxford Academic. (2024, May 6). Multicolour photometry of LEO mega-constellations Starlink and OneWeb. Monthly Notices of the Royal Astronomical Society. https://academic.oup.com/mnras/article/530/4/5006/7669132
22. Springer. (2022, February 3). Precise orbit determination for BDS satellites. Satellite Navigation. https://satellite-navigation.springeropen.com/articles/10.1186/s43020-021-00062-y
23. PMC. (2013). Experimental study on the precise orbit determination of the BeiDou Navigation Satellite System. https://pmc.ncbi.nlm.nih.gov/articles/PMC3658722/
24. ScienceDirect. (2016, June 11). Improvement of orbit determination accuracy for Beidou Navigation Satellite System with Two-way Satellite Time Frequency Transfer. https://www.sciencedirect.com/science/article/abs/pii/S0273117716303052
25. Wikipedia. (2025). BeiDou. https://en.wikipedia.org/wiki/BeiDou
26. GPS World. (2025, August 21). New satellite orbit determination method could boost navigation precision for future mega-constellations. https://www.gpsworld.com/new-satellite-orbit-determination-method-could-boost-navigation-precision-for-future-mega-constellations/
27. Springer. (2017, February 3). Enhanced orbit determination for BeiDou satellites with FengYun-3C onboard GNSS data. GPS Solutions. https://link.springer.com/article/10.1007/s10291-017-0604-y
28. Springer. (2023, November 6). Precise orbit determination of Haiyang-2D using onboard BDS-3 B1C/B2a observations with ambiguity resolution. Satellite Navigation. https://satellite-navigation.springeropen.com/articles/10.1186/s43020-023-00118-1
29. Springer. (2023, February 9). BDS-3 precise orbit and clock solution at Wuhan University: status and improvement. Journal of Geodesy. https://link.springer.com/article/10.1007/s00190-023-01705-5
30. GPS World. (2024, November 15). BeiDou Navigation Satellite System in 2024. https://www.gpsworld.com/beidou-navigation-satellite-system-in-2024/
31. Springer. (2020, January 20). Basic performance and future developments of BeiDou global navigation satellite system. Satellite Navigation. https://satellite-navigation.springeropen.com/articles/10.1186/s43020-019-0006-0
32. New satellite orbit determination method could boost navigation precision for future mega-constellations - GPS World