Toru Takahashi, Susumu Saito, Mitsunori Kitamura, and Takeyasu Sakai, Electronic Navigation Research Institute, National Institute of Maritime, Port, and Aviation Technology, Japan

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Abstract:

The current Satellite-Based Augmentation System (SBAS) based on the GPS L1 signals broadcasts augmentation messages from geostationary (GEO) satellites, which is not available practically in the polar region at a latitude of 72 degrees or higher. The Japanese Quasi-Zenith Satellite System (QZSS) also provides the augmentation message for GPS, Galileo, and GLONASS based on the ground observation. The inclination of QZSS is about 42 degrees so that there is a possibility to receive the augmentation message in the Arctic. The Electronic Navigation Research Institute (ENRI) developed a Dual-Frequency and Multi-Constellation (DFMC) SBAS prototype based on the draft standards. Thus, the objectives of this study are to evaluate the performance DFMC SBAS broadcasted from Japanese QZSS in the Arctic and high latitudes region. We installed the GNSS antenna and receiver on the roof of the chemistry building of University of Oslo, Norway on February 24, 2021 and continuously conducted the experiment to March 17, 2021. By using the broadcasted augmentation message, from 30 to 70% of observed satellites were corrected. The augmentation message improved the mean positioning accuracy, but the positioning variation increased because of the reduce of the number of calculated satellites. The horizontal protection level was calculated and compared with the positioning error. The positioning error did not exceed the protection level. We assumed the protection level utilized to the Localizer Performance with Vertical Guidance (LPV), and horizontal availabilities was calculated. Those were 83.2, 97.0, and 100% for 6 or more, 8 or more, and 11 or more augmented satellites. If we utilize the DFMC SBAS augmentation message for LPV, we need 11 or more augmented satellites. However, that cause is 17.2% of total time currently. In near future, the satellite transmitting L1/E1 and L5/E5a and the reference stations are going to be expanded and thus, this percentage and number of augmented satellites will increase. Therefore, the more estimation of the DFMC SBAS broadcasted by the QZSS are needed.