Multi-constellation Dual-Frequency SBAS

The Satellite Based Augmentation System (SBAS) concept was initially devised to provide GPS navigation augmentation services to civil aviation over wide areas because GPS standalone solutions had not met the civil aviation requirements, in particular as regards the level of integrity required for certain flight operations. In addition to the integrity information on GPS satellites, SBAS systems broadcast orbit and clock corrections to improve the accuracy of the ranging measurements from GPS satellites, and thereby improve the accuracy of the navigation solution. It is to be noted that since WAAS' pioneering development, other SBAS systems have proliferated worldwide: MSAS in Japan, GAGAN in India and EGNOS in Europe have been declared operational and available for civil aviation. Other SBAS systems are in development or validation phases, such as the Russian SDCM, while others are under preliminary study phases as it is the case of SACCSA program in Latin-America or the Korean SBAS, which is expected to start its first operations by 2020. In conjunction with this geographical extension of the SBAS coverage through the new service providers, SBAS systems are also expected to support, at least in certain regions, additional multi-modal services for the land and maritime community beyond the originally targeted aeronautical users. Given the inherent complexity of any SBAS system, it is quite frequent that SBAS development plans envisage the deployment of testbeds and pre-operational, non-certified, services prior to the first stages of the development of the operational system. Testbeds offer numerous advantages, in particular, they provide the system developers or standard designers with powerful platforms to early validate new concept architectures, first design solutions, performance assumptions and system evolutions, thus greatly mitigating design risks and helping to optimize the design to satisfy the requirements of the system. magicSBAS is a state-of-the-art real time and post processing operational SBAS testbed developed by GMV to offer non-safety critical SBAS augmentation to any interested region or organization. Recent advances introduced in magicSBAS tool suite such as multi-constellation and multi-frequency processing are here being presented in order to benchmark certain algorithm evolutions proposed to target the SBAS adaptation or enhancements mentioned previously. magicSBAS' capacity has been upgraded to: Run experimentations with both synthetic and real data considering not only GPS, but also GLONASS, Galileo and BeiDou satellites. This includes not only the necessary means for the generation of multi-constellation synthetic scenarios but also the ability to ingest the available real data coming from data files (e.g.; RINEX) or real time sources (e.g.; EDAS or NTRIP) into magicSBAS processing chain. Provide solution in both single-frequency and dual-frequency augmentation modes including satellite integrity information based either on MT27 or MT28 messages. Support GEO ranging based on GEO satellites implementing classic propulsion system as well as ionic propulsion. Handle external estimations of the satellite clocks and orbits, both in post-processing and real-time mode, to improve the ranging accuracy. With those configurations, performances have been successfully tested in different scenarios using real and synthetic data. Promising results are shown in the paper presented.