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Abstract

Geospatial Information Authority of Japan (GSI) is currently developing technologies for GNSS precise orbit determination. The project is performed in collaboration with the Japan Aerospace Exploration Agency (JAXA). We use MADOCA software developed by JAXA to estimate precise orbits for GNSS that include Japan’s satellite system QZSS (Quasi-Zenith Satellite System), as well as GPS and GLONASS. The GNSS precise orbit determination project has important aspects. Firstly, it improves the redundancy of our daily station coordinates of Japan’s GNSS CORS network named GEONET, which consists of over 1,300 stations. At present, the routine analysis completely depends on IGS products. Our results are used to relate the current position with the position aligned to JGD2011, and also used as the basis for real-time high-precision positioning services including Centimeter Level Positioning Augmentation Service (CLAS). Therefore, our own orbit products aligned with the ITRF is important to reduce the dependency of the products on external organizations only. Secondly, QZSS is scheduled to reach a total of seven satellites during FY2023 and FY2024. Thus, it is essential to provide precise QZSS orbits aligned with national geodetic datum, likewise GPS and GLONASS. We reprocessed data for November to December 2020 and assessed the results. Due to the software update that make sure more consistent with the conventions and modeling in IGS repro3, our results well aligned with IGS combined solutions. The consistency is almost comparable to other IGS analysis centers. In our presentation, we will present further results for long-term reprocessing under the framework of repro3.