Real-time precise point positioning with ambiguity resolution (PPP-AR) is increasingly important for Global Navigation Satellite System (GNSS) navigation, timing, and other time-critical applications. Its performance depends on real-time satellite orbit and clock products delivered through services such as the International GNSS Service (IGS) Real-Time Service (RTS). Earlier work shows that real-time products are less accurate than final post-processed products, especially for some constellations, while multi-frequency and multi-GNSS observations improve convergence. However, reported convergence times come from different datasets, product streams, processing strategies, and evaluation criteria, making direct comparisons difficult. Given these challenges, in-depth research is needed on how archived real-time and post-processed precise products compare under a common PPP-AR framework.
A study led by researchers at Technische Universität Berlin and the GFZ Helmholtz Centre for Geosciences, with collaborators from Chang'an University, was published (DOI: 10.1186/s43020-026-00222-y) online on 07 October 2026 in Satellite Navigation. The team processed 31 days of data from 249 Multi-GNSS Experiment (MGEX) stations using archived real-time products from Centre National d’Études Spatiales (CNES) and Wuhan University (WHU), plus final WHU products. They evaluated dual- and triple-frequency PPP-AR for Global Positioning System (GPS), Galileo, and Third-generation BeiDou Navigation Satellite System (BDS-3) solutions under continuous correction availability to isolate product-stream effects.
The analysis compared real-time CNES/CLS (RT-CNES), real-time WHU (RT-WHU), and final WHU (FIN-WHU) streams. In single-constellation PPP-AR, convergence remained strongly tied to product quality. For GPS-only triple-frequency PPP-AR in the vertical component at the 10 cm threshold, the 68.3rd-percentile ensemble convergence time was about 26.5 minutes with RT-WHU and 15.5 minutes with FIN-WHU. For GPS+Galileo+BDS-3, those times fell to about 6.5 and 1.5 minutes, showing that multi-GNSS integration sharply reduces sensitivity to product-stream differences. Yet strict thresholds exposed larger gaps. For GPS-only vertical solutions, the ensemble time was about 13.0 minutes with real-time products and 10.5 minutes with FIN-WHU at 20 cm, but rose to about 71.0 and 24.0 minutes at 5 cm. Narrow-lane (NL) ambiguity fractional-cycle residuals were far more product-dependent than extra-wide-lane (EWL) and wide-lane (WL) residuals. FIN-WHU showed the smallest orbit and clock differences, and RT-WHU generally outperformed RT-CNES, especially for BDS-3. Ambiguity resolution improved convergence over float PPP, and triple-frequency observations helped PPP-AR more than float solutions. BDS-3 Inclined Geosynchronous Orbit (IGSO) satellites improved Asia-Pacific geometry but also increased regional dependence. At the 90th percentile and under tighter arc-wise root-mean-square (RMS) criteria, real-time streams degraded faster than FIN-WHU.
The authors said the results should be viewed as a favorable benchmark, not a guarantee of operational real-time performance. They explained that the archived real-time streams were processed offline under continuous correction availability, so correction latency, stream interruptions, and outage-induced reinitialization were not considered.. Under those controlled conditions, real-time PPP-AR can reach moderate centimeter-level accuracy, but the gap to final products grows quickly when users demand stricter accuracy. They added that multi-GNSS integration is a powerful buffer, while single-constellation users remain more exposed to product quality.
These findings matter for autonomous driving, precision agriculture, deformation monitoring, atmospheric sensing, and other real-time GNSS applications. Users with moderate centimeter-level needs may benefit from multi-GNSS, multi-frequency PPP-AR even with real-time products, provided corrections are stable. For strict accuracy targets, however, final post-processed products remain more reliable, and single-constellation users should expect longer convergence. The study also highlights the need for long-term, high-rate tests using operational real-time streams, because correction latency and outages can further degrade performance. Atmospheric augmentation and regional corrections may help accelerate real-time PPP-AR in the future for high-precision positioning, navigation, and timing.
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References
DOI
10.1186/s43020-026-00222-y
Original Source URL
https://doi.org/10.1186/s43020-026-00222-y
Funding information
The work is funded by the China scholarship council (CSC No. 202206560005), the German Research Foundation (DFG) Project: Combination of Space Geodetic Techniques with Clock Ties and Atmospheric Ties (No. 490990195), the National Natural Science Foundation of China (No. 42404027), the Key Research and Development Program of Shaanxi Province (2025CYYBXM-054), and the China Postdoctoral Science Foundation (No. 2025T180061, No. 2024M762766).
About Satellite Navigation
Satellite Navigation (ISSN: 2662-1363; ISSN: 2662-9291) Satellite Navigation is the official journal of the Aerospace Information Research Institute. The journal aims to report innovative ideas, new results, and progress in the theories, techniques, and applications of satellite navigation. The journal welcomes original articles, reviews and commentaries.