Approach to Utilizing SFMC SBAS Message for Dual-frequency Users to Enable Universally Applicable SBAS

The current L1 Legacy SBAS provides satellite orbit and clock corrections, as well as ionospheric delay corrections, for single-frequency users. Although Dual-Frequency Multi-Constellation (DFMC) SBAS, which augments multi-constellation GNSS using the L5 signal, has recently been standardized, the number of receivers supporting L5 is lower than that of those supporting L2, and the number of receivers supporting both L1 and L5 is significantly smaller than those supporting L1 and L2 (European Global Navigation Satellite Systems Agency 2018). This study proposes a method that enables both single-frequency users and dual-frequency users to utilize SBAS services through Single-Frequency Multi-Constellation (SFMC) SBAS. Our previous research on SFMC SBAS modifies the L1 Legacy SBAS message to provide services for multi-constellations using the L1 signal (Lim et al., 2020, 2023). In this study, we utilized SFMC SBAS to enable various dual-frequency users to utilize SBAS services by compensating for the single-frequency satellite clock bias using navigation parameters provided in the broadcast ephemeris. Static field tests confirmed the accuracy improvement of L1 GPS, SFMC, and SFMC for dual-frequency users, demonstrating the potential for a more universally applicable SBAS service.