A UK satellite-based augmentation system has been successfully demonstrated on a test flight for the first time.
A satellite-based augmentation system (SBAS) improves the accuracy and reliability of satellite navigation systems like GPS by combining it with regional ground monitoring data to correct errors and provide information about signal reliability and avialability.
SBAS can offer positioning down to a few centimeters of accuracy, rather than the few metres provided by standard global navigation satellite systems. SBAS gives pilots greater trust in onboard instruments and is vital if pilots cannot physically see a runway or other obstacles because of bad weather.
The UK was a member of Europe’s SBAS, the European Geostationary Navigation Overlay Service (EGNOS), but lost access when it left the EU in 2021.
UK SBAS generates an overlay test signal to the US Global Positioning System (GPS), fully compliant with International Civil Aviation Organization (ICAO) standards. Broadcast capability for UK SBAS is being provided by Viasat's I-3 F5 satellite.
Viasat's research with a regional flight operator indicates that close to 40% of flights canceled due to weather could have gone ahead had UK SBAS been available for its fleet. Around the UK, 19 airports had EGNOS procedures in place before leaving the EU. In total, as many as 72 airports no longer have access.
Flight testing UK SBAS
While EGNOS can still be used for non-safety applications in the UK, the trial aims to provide a first step toward a UK SBAS which can be used for critical safety of life navigation services across air, land, and sea.
The test flight was flown from Cranfield Airport, UK using the National Flying Laboratory Centre's Saab 340B aircraft. With the aviation test complete, the trial is aimed to test the system in other transport applications, for example for rail, uncrewed aerial vehicles, or autonomous road vehicles.
The trial is being run by a Viasat-led team of companies, which as well as the National Flying Laboratory Centre includes Goonhilly Earth Station, IT firm CGI UK, Spanish aerospace technology companies GMV and Pildo Labs, Ordnance Survey and Cranfield University.
Todd McDonnell, president of international government at Viasat said, "In the future, we will be able to use highly accurate tracking to develop Britain's transport system as new technologies come into play. We're excited to continue the trial and see how far we can take it."
Technology Minister at the UK’s Department for Transport, Anthony Browne said, "The project, fully funded by the UK Government, is directly supporting our work on future provision of high-accuracy, high-integrity positioning services, which could increase efficiency and enable new innovations across the transport network."
A similar system to the UK SBAS, known as SouthPAN is being developed to make resilient positioning, navigation and timing (PNT) available in Australia and New Zealand. Signals for the service would be provided by Viasat through one of its next-generation I-8 satellites, which are aimed to launch in 2027.