Galileo High Accuracy Service Declared Operational

The Galileo High Accuracy Service (HAS) was officially declared available to users at the European Space Conference in Brussels, Belgium. The announcement follows months of testing by ESA engineers at the ESTEC technical center in the Netherlands.

“This new High Accuracy Service offers a new dimension of precision to everyone who needs it, while the Open Service Navigation Message Authentication – already available – allows users to authenticate Galileo signals as they make use of it, to minimize any risk of spoofing."

Javier Benedicto, ESA Director of Navigation.

The new High Accuracy Service correction message is embedded within the ‘E6’ band of the Galileo signal – typically not accessed via smartphones and other mass-market products but only through high-end receivers. However this message is also being made available through the internet, opening the prospect of wider adoption by connected devices, and its development into the Open Service standard in years to come.

“Galileo is not standing still,” said Javier Benedicto, ESA Director of Navigation. “This new High Accuracy Service offers a new dimension of precision to everyone who needs it, while the Open Service Navigation Message Authentication – already available – allows users to authenticate Galileo signals as they make use of it, to minimize any risk of spoofing. And an upgraded integrity message of the signal rolled out last year reduces the time to first fix while enhancing the overall robustness of Galileo.

“ESA’s role is to oversee such fundamental upgrades to the Galileo system, working in conjunction with Galileo’s service provider EUSPA, the EU Agency for the Space Program, and its owner, the European Union. Further service improvements will come with the launch of the remaining Galileo satellites, followed later this decade by Galileo Second Generation.”

Galileo High Accuracy Service Offers Improved Precision

The new Galileo High Accuracy Service further improves on this performance through the use of a High Accuracy Data Generator based at the Galileo Control Center in Fucino, Italy, generating additional corrections for Galileo as well as US GPS satellites. These corrections are then relayed to compatible receivers in real time through the Galileo satellite signal – compiled into a single message of 448 bits per second, a unique capability of the carefully-engineered Galileo signal shape.

“Compared to the Galileo Open Service, the corrections are made available very rapidly and very often – with an update for satellite orbits every 30 seconds and for satellite clocks every 10 seconds,” explains ESA’s Galileo System Performance Engineer Daniel Blonksi. “And the HAS correction message is designed in such a way that suitable receivers can benefit from multiple satellites broadcasting it, to reconstruct the overall message very fast.”

The new high accuracy service is envisaged as having two service levels. Service Level 1, already available, corrects satellite orbit and clock errors as well as internal signal ‘biases’ unique to each satellite in the constellation that, once known, can enable still higher precision through direct comparisons of their signal phase.

Service Level 2, intended for roll out across Europe, will combine these with additional ionospheric corrections, made possible by the use of additional ground stations for which ESA is preparing the needed infrastructure upgrades.

(Images provided with ESA news release)