Acta Geodaetica et Cartographica Sinica ›› 2026, Vol. 55 ›› Issue (6): 1018-1030.doi: 10.11947/j.AGCS.2026.20260051

• Geodesy and Navigation • Previous Articles    

Phase Wind-up and precise point positioning considering GNSS satellite attitude

Xuexi LIU1,2(), Guanghan LIU1, Chao YANG3, Nanshan ZHENG1(), Fudong GUO1, Kefei ZHANG1, Shimao DOU1   

  1. 1.School of Environmental and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, China
    2.Hubei Luojia Laboratory, Wuhan 430079, China
    3.Department of Land Surveying and Geospatial Science, The Hong Kong Polytechnic University, Hong Kong 999077, China
  • Received:2026-02-02 Revised:2026-05-20 Published:2026-07-28
  • Contact: Nanshan ZHENG E-mail:xuexiliu@cumt.edu.cn;znshcumt@cumt.edu.cn
  • About author:LIU Xuexi (1992—), male, PhD, associate professor, majors in GNSS precise data processing and space geodesy. E-mail: xuexiliu@cumt.edu.cn
  • Supported by:
    The Natural Science Foundation of Jiangsu Province(BK20231087);The National Natural Science Foundation of China(42304015; 42274049);Jiangsu Provincial Natural Resources Science and Technology Project(JSZRKJ202510);The Open Fund of Hubei Luojia Laboratory(250100007);China Postdoctoral Science Foundation(2025T180062);General Project of China Postdoctoral Science Foundation(2024M753525);Jiangsu Province Youth Science and Technology Talent Support Project(JSTJ-2024-075);Key Program of the National Natural Science Foundation of China(U22A20569)

Abstract:

Satellite attitude models influence variations in the Yaw angle, thereby changing the line-of-sight projection of the satellite antenna phase center offset (PCO) and the phase Wind-up correction, and ultimately affecting the modeling and positioning results of precise point positioning (PPP). Such effects become more pronounced under attitude-sensitive conditions, such as low-β angles and eclipse periods. In this study, attitude quaternion products (OBX/ORBEX) released by the International GNSS Service (IGS) are introduced. Under a unified PPP processing strategy and with consistent precise products from the same analysis center, differences between the nominal attitude model and quaternion-based attitude products from four analysis centers—Wuhan University (WUM), the Center for Orbit Determination in Europe (CODE), the German Research Centre for Geosciences (GFZ), and the Groupe de Recherche de Géodésie Spatiale (GRG)—are compared for four GNSS constellations: GPS, BDS, Galileo, and GLONASS. Their impact path is further investigated along the “Yaw-PCO-Wind-up-PPP” chain. The results show that, within attitude maneuver windows, Yaw angles can undergo rotations close to±180°, and different analysis centers exhibit discrepancies in maneuver evolution and branch selection. The attitude-induced PCO differences are 2~3 cm for GPS, 0.7~0.8 cm for BDS, about 1 cm for Galileo, and up to 10~16 cm for GLONASS. Phase wind-up differences are also significant during maneuver periods, reaching 0.8~1.0 cycles for GPS and BDS, while being relatively smaller for Galileo and GLONASS, at 0.2~0.4 cycles. Three-day PPP results and multi-station statistics indicate that quaternion-based attitude products can reduce the three-component PPP RMS in most cases, but the improvement exhibits clear system-dependent and analysis-center-dependent characteristics. Specifically, the improvement for GPS is limited, with a maximum of 7.96%; BDS shows the most significant improvement, reaching up to 22.05%; Galileo performs relatively stably, with a maximum improvement of 13.39%; and GLONASS shows relatively small improvement, with a maximum of 7.78%. Slight degradation may still occur in a few combinations, with a maximum of about-0.89%. In summary, quaternion-based attitude products can significantly affect PPP accuracy during attitude-sensitive periods, but their practical application still requires system-specific and analysis-center-specific evaluation and quality control.

Key words: satellite attitude, quaternion, Yaw angle, phase Wind-up, phase center offset, precise point positioning

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