Viasat has demonstrated a UK satellite-based augmentation system (UK SBAS) for the first time, showing how highly accurate GPS data can maximize safety and improve efficiency. The test flight, flown from Cranfield Airport using the National Flying Laboratory Centre's Saab 340B aircraft, showcased a UK-based SBAS that delivers more precise, reliable navigation data.

The UK is no longer part of the EU's similar European Geostationary Navigation Overlay Service (EGNOS), following its exit from the European Union. While EGNOS can still be used for non-safety applications in the UK, the trial aims to provide a first step toward a complementary UK SBAS which can be used for critical safety of life navigation services across air, land, and sea.

UK SBAS works by combining ground monitoring data with satellite connectivity to provide more reliable navigational data. Across a range of applications, it can offer positioning down to a few centimeters of accuracy, rather than the few metres provided by standard GPS. For aviation, the system gives pilots greater trust in their onboard instruments, which has major implications when pilots may not be able to physically see a runway or other obstacles due to bad weather.

This means improved safety and fewer missed landings because pilots – especially smaller aircraft flying into regional airports and general aviation airfields – can get significantly closer to the ground during an approach before making the decision whether to land. Viasat's research with one regional flight operator indicated that close to 40% of flights cancelled 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 prior to leaving the European Union. In total, as many as 72 airports no longer have access.

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.

Technology Minister at the Department for Transport, Anthony Browne said "This successful demonstration illustrates the UK's first-class space sector, and our capabilities in position, navigation and timing specifically."

"The project, fully funded by the Government through the ESA NAVISP program, 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."

Todd McDonnell, President, of International Government, Viasat, said "This trial on a sovereign UK SBAS is all about delivering trust. Trust for pilots in their tracking systems so they can stay safe in challenging conditions. Trust for the aviation industry more broadly so it can rely on data to operate more efficiently. And, in the future, trust that we can 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."

Dean Thomas, Position, Navigation and Timing Lead at the UK Space Agency, said "This testbed project is vital in helping the Government understand the potential benefits of a UK SBAS. The flight trial both demonstrates the capability of UK industry in delivering space-based PNT solutions and illustrates the benefits of delivering UK PNT projects facilitated by ESA, through the highly flexible NAVISP program."

About the project

With funding from the Department for Transport via the European Space Agency's NAVISP program, the trial is being completed by a Viasat-led team of companies in the UK, including Goonhilly Earth Station, CGI UK, GMV, Ordnance Survey, Cranfield University, the Cranfield National Flying Laboratory Centre, and Pildo Labs.

UK SBAS generates an overlay test signal to the US Global Positioning System (GPS), fully compliant with International Civil Aviation Organization (ICAO) standards, to enable assessment of more precise, resilient, and high-integrity navigation for maritime and aviation users in UK waters and airspace. The signal is being broadcast in coordination with the US Federal Aviation Administration (FAA), the European Space Agency (ESA), and the European Union Space Programme Agency (EUSPA). Broadcast capability for UK SBAS is being provided by Viasat's I-3 F5 satellite.

A similar system, known as SouthPAN, is currently 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.