TAMPA, Fla. — Viasat has successfully demonstrated a satellite navigation signal on an airplane that could help the United Kingdom replace capabilities lost after leaving the European Union, the operator announced Jan. 18. 

A Saab 340B turboprop plane used a positioning, navigation, and timing (PNT) overlay signal from I-3 F5, Viasat’s 24-year-old satellite, to improve GPS accuracy during an hour-long test flight late last year over Cranfield, England.

“The test met expectations and was successful,” Viasat vice president of strategic programs and partnerships Gary Lay told SpaceNews, and involved four separate runway approaches.

Lay declined to disclose specific performance details. The tests aimed to show how the signal from a repurposed I-3 F5 transponder could improve positioning accuracy to a few centimeters, compared with the few meters provided by standard GPS alone.

Greater accuracy enables aircraft to make more high-precision landing approaches with less costly navigation support from the ground, with important safety implications for pilots unable to see a runway or other obstacles in bad weather. 

The United Kingdom lost access to the European Geostationary Navigation Overlay Service (EGNOS) for safety-related applications in 2021 following Brexit. 

According to Viasat, 19 airports across the United Kingdom had EGNOS procedures in place before the country left the European Union, and nearly 40% of flights one regional operator canceled due to weather could have gone ahead if a sovereign alternative had been in place. 

The operator is leading a group of local companies to develop a UK Space-Based Augmentation System (UKSBAS) for replacing EGNOS, supported by funding from the British government.

With aviation tests wrapped up, the group plans to show how the system could also be used for rail, uncrewed aerial vehicles, and autonomous road vehicles.

Viasat has three small satellites on order, slated to launch in 2027, that will carry navigation transponders to support the service after I-3 F5 runs out of fuel.

One of these satellites will support a similar GPS overlay system for Australia and New Zealand, called the Southern Positioning Augmentation Network (SouthPAN), following a government contract worth roughly $123 million.

Jason Rainbow writes about satellite telecom, space finance and commercial markets for SpaceNews. He has spent more than a decade covering the global space industry as a business journalist. Previously, he was Group Editor-in-Chief for Finance Information...