magicSBAS is a state-of-the-art, multi-constellation, operational Satellite Based Augmentation System (SBAS) testbed developed by GMV to offer SBAS regional differential corrections and non-safety critical integrity augmentation to any interested region, and it is being extensively used in different SBAS programs worldwide for engineering and demonstration purposes.
When connected to RTS, magicSBAS uses the external orbit and clock corrections instead of its internal algorithms to generate the SBAS satellite long term and fast messages. The correction bounds, the UDREs, are still computed internally with real time measurements from a regional network of reference stations to ensure integrity within the demanding SBAS time to alert. Special care is paid to the estimation of the offsets between the different time scales used by the external provider and the SBAS solution and to refer each satellite clock to C/A code, as requested in SBAS L1. This new execution mode of magicSBAS has been shown to double the accuracy of the satellite ranging error at worst user locations (SREW) within its service area.
Integration with RTS is not the only improvement in the new version of magicSBAS. In addition to enhanced robustness and better connectivity to combined sources of real time raw measurements data, such as NTRIP and EGNOS EDAS raw data, the tool upgrade can be configured to use dynamic PRN masks. The SBAS L1 standard limits the number of satellites to be augmented simultaneously to 51. Where two or more GNSS core constellations are to be covered, it would be necessary either to preselect a subset of satellites or to change the PRN mask at regular intervals to augment a different set of satellites, a technique known as “dynamic PRN mask”.
For the first time ever, a real time SBAS testbed implements such a functionality. The mask is modified at rates in the range of one hour, optimizing the performance in the worst user location of the service area. The initial tests run with GPS and GLONASS constellations show outstanding performance in the number of monitored satellites and vertical dilution of precision at the worst user location. For instance, the minimum number of monitored satellites at the worst user of a list of representative locations throughout the European continent rises from 8 to 12.
This recent evolution of magicSBAS is the result of GMV’s determined commitment to innovation in GNSS, and more particularly in SBAS data processing.
