• Sorted by Date • Sorted by Last Name of First Author •
Hou, Cong, Jin, Xiaojun, Yang, Xiaopeng, and Xiao, Tong, 2025. Toward Robust GNSS Real-Time Orbit Determination for Microsatellites Using Factor Graph Optimization. Remote Sensing, 17(7):1125, doi:10.3390/rs17071125.
• from the NASA Astrophysics Data System • by the DOI System •
@ARTICLE{2025RemS...17.1125H, author = {{Hou}, Cong and {Jin}, Xiaojun and {Yang}, Xiaopeng and {Xiao}, Tong}, title = "{Toward Robust GNSS Real-Time Orbit Determination for Microsatellites Using Factor Graph Optimization}", journal = {Remote Sensing}, keywords = {microsatellite, real-time orbit determination, GNSS, factor graph optimization, sliding window}, year = 2025, month = mar, volume = {17}, number = {7}, eid = {1125}, pages = {1125}, abstract = "{Extended Kalman Filter (EKF) is extensively employed in Global Navigation Satellite System (GNSS)-based real-time orbit determination (RTOD) for microsatellites due to its low complexity. However, the performance of EKF-RTOD is markedly degraded when the microsatellite deviates from a stable Earth- pointing attitude and employs a low-cost receiver. Factor graph optimization (FGO), which addresses nonlinear problems through multiple iterations and re-linearization, has demonstrated superior accuracy and robustness compared to EKF in challenging environments such as urban canyons. In this study, we introduce a novel FGO-based RTOD (FGO-RTOD) approach, which integrates state transfer factors to establish temporal connections between state nodes across multiple epochs. Real-time processing is achieved through a sliding window mechanism combined with marginalization. This paper evaluates the performance of the proposed algorithm in a regular scenario using data from GRACE- FO-A, which maintains the Earth-pointing attitude and employs a high-performance receiver. The positioning results of GRACE-FO-A indicate that FGO-RTOD marginally outperforms EKF-RTOD in accuracy. Furthermore, the performance of FGO-RTOD is assessed in challenging scenarios using simulation data and on-orbit data from Tianping-2B microsatellite, which is not in an Earth- pointing attitude and employs a low-cost receiver. The simulation results reveal that FGO-RTOD reduces the Root Mean Square (RMS) of positioning error by 79.0\% relative to EKF-RTOD and exhibits significantly enhanced smoothing. In the Tianping-2B experiments, FGO-RTOD reduces the RMS of carrier- phase ionosphere-free combination residuals from 2 cm to 1 cm relative to EKF-RTOD, alongside a substantial improvement in the ratio of valid observations. These findings underscore the effectiveness of FGO-RTOD in managing outlier measurements in challenging scenarios.}", doi = {10.3390/rs17071125}, adsurl = {https://ui.adsabs.harvard.edu/abs/2025RemS...17.1125H}, adsnote = {Provided by the SAO/NASA Astrophysics Data System} }
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