Satellite Based Augmentation System (SBAS) is a system to augment Global Positioning System (GPS) by differential corrections and integrity information with a low data rate of 250 bps from a geostationary satellite. All the current operating SBAS systems except for the System for Differential Corrections and Monitoring (SDCM) in Russia support only GPS. This means that most of Global Navigation Satellite System (GNSS) receivers that support multi-constellation cannot fully utilize the advantages (e.g. improving Dilution of Precision (DOP) and the accuracy) of multi-constellation when applying the SBAS augmentations. To overcome this limitation, we applied the L1 Single-Frequency, Multi-Constellation (SFMC) SBAS. To generate the long-term satellite error corrections, we used the precise orbit and clock products provided by International GNSS Center (IGS) analysis centers. Also, we computed the ionospheric delay corrections for multi-constellation GNSS using vertical delay estimates at the Ionospheric Grid Point (IGPs) from MSAS Message Type 26. We conducted an experiment to confirm the effect of the L1 SFMC SBAS in South Korea where typically about 30~40 GNSS (GPS, GLONASS, Galileo, QZSS and BeiDou) satellites are observed. As a result, the RMS errors have been reduced from 0.8049 m to 0.6073 m horizontally, and from 0.9982 m to 0.7728 m vertically

Keywords: SBAS, single-frequency, multi-constellation