Real-Time Precise Orbit and Clock Errors Bounding for High Integrity PPP

Yingchao Xiao, Xingqun Zhan, Yawei Zhai

Peer Reviewed

Abstract: To apply real-time Precise Point Positioning (PPP) into safety-critical applications, such as autonomous driving cars and Urban Air Mobility (UAM), the requirement of integrity should be met. As the basis of PPP integrity monitoring, prior assumptions/assertions on the State-Space Representation (SSR) corrections of satellite orbits and clocks are essential. To obtain the prior information, we analyze the GPS corrections from integrity perspective. Correction errors are obtained by comparing one-year data provided by Centre National d’Etudes Spatiales (CNES) to International GNSS (Global Navigation Satellite System) Service (IGS) final precise products. To analyze the error characteristics from user end, orbit and clock errors are projected into the Line-of-Sight (LOS) direction. Nominal samples of which outliers are removed are utilized for accuracy analysis. Root Mean Square (RMS) results show that orbit error in along direction has the worst performance and clock error dominates the line-of-sight range error. Kurtosis test shows that the superGaussian distributions with lighter tails are suitable for the orbit and clock errors. A conservative quality indicator (QI) is obtained by bounding the actual error using a normal distribution. Different QIs are estimated at various confidence levels. The range of QI values are 0.048-0.244m at the confidence level of 10-2 , 0.068-0.244m at 10-3 , 0.093-0.657m at 10-4 and 0.093-0.717m at 10-5, respectively.
Published in: Proceedings of the 36th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2023)
September 11 - 15, 2023
Hyatt Regency Denver
Denver, Colorado
Pages: 2504 - 2513
Cite this article: Xiao, Yingchao, Zhan, Xingqun, Zhai, Yawei, "Real-Time Precise Orbit and Clock Errors Bounding for High Integrity PPP," Proceedings of the 36th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2023), Denver, Colorado, September 2023, pp. 2504-2513. https://doi.org/10.33012/2023.19194
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