Zero downtime for GNSS applications
Global navigation satellite systems (GNSS) may be an integrant part of our daily lives – to the point where we rely on them for most unusual travels – but they are still far from infallible. One phenomenon known as ionospheric disturbance, where solar flares cause a sudden increase in radio-wave absorption that often delays the propagation of signals and ultimately affects positioning, has been keeping researchers busy for years. The CALIBRA project team has been participating to this global research effort with a particular focus on Brazil, which is one of the most exposed regions due to its proximity to the magnetic equator. This has to be further added to the fact that the sun is at its peak of activity since it entered its new 11-year cycle in 2010. Now, after 27 months of intensive research, the CALIBRA team have just come up with exciting new solutions to counter the ionospheric disturbance problem. They recently showcased a commercially applicable approach to mitigate the phenomenon’s impact on high accuracy GNSS positioning techniques, thanks to two real-life demonstrations where their newly developed algorithm was tested in actual precision agriculture and offshore operations. A tremendous potential The project consisted of three major steps. First, the team confirmed that ionospheric scintillation and variations in total electron content (TEC) had a direct impact on the functioning of GNSS Precise Point positioning (PPP) and Real Time Kinematic (RTK) positioning – techniques that provide centimetre level accuracy thanks to the use of reference stations – after which they characterized the disturbances with a suitable metric. Then, the project produced a short-term empirical model for forecasting TEC and scintillation. The latter was tested using the CIGALA-CALIBRA network and database – a network of ionospheric scintillation monitor receivers with a web interface (the ISMR Query tool) which collects over 10 million observations on GPS, Glonass, Galeleo Beidou and other global navigation systems every day. Since it was launched in December 2014, this data has helped assist users from over 20 countries thanks to the software’s visualisation and mining techniques. In light of this success, CALIBRA partners filed a patent for their forecasting model and a new spin-off company, SpacEarth Technology, was set up. SpacEarth’s main purpose is to secure the software’s commercialisation in relevant applications and services, while also improving and adapting it to evolving market needs. One of the first realisations of the new company is a firmware update for project partner Septentrio’s GNSS receivers. The latter also built on the project’s outcomes to create a next generation RTK engine including a new model for estimating ionospheric delay, which has already proven valuable for very long baseline RTK and for mitigating ionospheric effects. In addition to this competitive edge, the project’s results promise to considerably reduce downtime and financial losses caused by ionospheric disturbance in Brazil and other regions of the world.
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