Benefits of Multi-GNSS and Multi-frequency Observations for GNSS Meteorology
Abstract
Multi-GNSS observations from permanent networks can be analysed for obtaining different precise products to support various applications. Besides global products, such as satellite orbits and clocks necessary for Precise Point Positioning (PPP), local augmentation services providing tropospheric parameters can be utilized in meteorology for severe weather forecasting.
In 2011, GOP initiated the development of the PPP-based troposphere monitoring in support of low-latency, high temporal resolution, anisotrophy monitoring, all strongly benefiting from the new multi-GNSS observations. We originally used a traditional processing strategy using code and carrier-phase observations forming the ionosphere-free linear combinations. Recently, we have also implemented a strategy utilizing undifferenced and uncombined observations which do not eliminate the first order of ionospheric delays and thus need to be modelled by introducing new parameters. Advantage of this strategy is that both tropospheric and ionospheric parameters can be estimated efficiently with high accuracy in a single processing run. In addition, processing uncombined observations gives us better flexibility in multi-frequency combination and optimal handling of individual signals. Thanks to this approach, we can study an impact of individual observations on estimated tropospheric parameters The Galileo system has not been in the full constellation yet, but it undergoes fast development, and Galileo stand-alone processing can already provide Zenith Tropospheric Delay (ZTD) at the milimeter level agreement compared to a multi-GNSS solution. We will demonstrate the evolution of the Galileo-only ZTD solution during the years 2018 and 2019. In addition, since new GNSS satellites provide observations for more than two legacy frequencies, we will also present the impact of the multi-frequency processing on the accuracy and robustness of ZTD estimates. The accuracy is calculated via comparison with the reference products and cross-validated when obtained at the nearby collocated stations. For application in real-time as well as in post-processing, we have used in our PPP solution orbits and clocks final products provided by the MGEX service and also real-time products disseminated via real-time streams.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.G21B0730V
- Keywords:
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- 3307 Boundary layer processes;
- ATMOSPHERIC PROCESSES;
- 1220 Atmosphere monitoring with geodetic techniques;
- GEODESY AND GRAVITY;
- 1294 Instruments and techniques;
- GEODESY AND GRAVITY;
- 1866 Soil moisture;
- HYDROLOGY