Analysis of a multi-GNSS clock offset combination using least-squares variance component estimation
| Autor: | Mansur, G., Brack, A., Sakic, P., Männel, B., Schuh, H. |
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| Rok vydání: | 2023 |
| Zdroj: | XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) |
| DOI: | 10.57757/iugg23-2408 |
| Popis: | The combined satellite clocks are one of the products provided by The International GNSS Service (IGS). These products are the result of a combination process that takes as input the individual solutions computed by the Analysis Centers (ACs). So far, only GPS and GLONASS combined products are distributed by the IGS. Since new constellations have been declared operational, such as Galileo in 2016 and BeiDou in 2018, a Multi-Constellation combination has been on focus. Therefore, we propose a method for a Multi-GNSS clock combination based on a least-squares framework, where the weights are determined by least-squares variance component estimation. The necessary alignments implemented in order to harmonize the solutions from the ACs will be demonstrated, such as radial correction between orbits and clocks, alignment of AC clocks to a reference AC through estimation of trends and offsets, and the inter-system bias correction between different systems. In addition, the outlier detection will be shown, which facilitates a reliable definition of a reference AC and consistent AC solutions. The results show that Galileo and GPS clocks have, on average, the best agreement between ACs and the combination, while GLONASS and QZSS have large variations. A validation of the combination is performed using the combined products as input in a Precise Point Positioning (PPP) processing, where the average residuals are below 10 mm, agreeing with the performance of the individual ACs. The 28th IUGG General Assembly (IUGG2023) (Berlin 2023) |
| Databáze: | OpenAIRE |
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