Numerical Modification to Speed Up the Convergence of Uncombined Precise Point Positioning
Publication: Journal of Surveying Engineering
Volume 149, Issue 2
Abstract
Ionosphere-free precise point positioning (IF PPP) and uncombined PPP (UC PPP) are commonly used PPP models. Although UC PPP is in theory more rigorous without loss of any measurement information, some researchers reported that UC PPP converges slower than IF PPP by using either Kalman filtering or sequential least-squares algorithms. In this paper, we will comprehensively study the cause of this contradiction from both theoretical and numerical points of view. The results show that the slower convergence of UC PPP is mainly attributed to the numerical instability due to the strong correlations between the ionospheric parameters and other parameters. We then propose a modified algorithm implementation to overcome such numerical instability and speed up the convergence of UC PPP.
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Data Availability Statement
Some data, models, or code used during the study were provided by a third party. Direct requests for these materials may be made to the provider as indicated in the Acknowledgments.
Acknowledgments
This work is supported by the National Natural Science Funds of China (42074026, 42104013, and 42225401), the Program of Shanghai Academic Research Leader (20XD1423800), the Innovation Program of Shanghai Municipal Education Commission (2021-01-07-00-07-E00095), the “Shuguang Program” supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission (20SG18), the Scientific and Technological Innovation Plan from Shanghai Science and Technology Committee (21511103902, 22511103003), and Natural Science Funds of Shanghai (21ZR1465600). The authors gratefully acknowledge IGS Multi-GNSS Experiment (MGEX) for providing GNSS data and products.
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Published In
Journal of Surveying Engineering
Volume 149 • Issue 2 • May 2023
Copyright
© 2023 American Society of Civil Engineers.
History
Received: Jan 21, 2022
Accepted: Nov 10, 2022
Published online: Jan 27, 2023
Published in print: May 1, 2023
Discussion open until: Jun 27, 2023
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