Europe’s largest ground segment updated with no user impact

With 30 satellites in orbit, Galileo is the world’s most precise satellite navigation system, providing metre-level accuracy to billions of users worldwide. At the heart of the Galileo system is its ground segment, the most complex ever developed, qualified and deployed in Europe. 

The two Control Centres, two Security Monitoring Centres, seven service entities and a worldwide network of uplink and sensor stations are essential to Galileo: they generate the Galileo navigation message, keep satellites on time, pinpoint their position and sense possible drift, process data and monitor the reliability of the constellation.

With Galileo’s First Generation close to completion, the ground segment required an upgrade to System Build 2.0 to bring critical enhancements to the system, especially for the roll-out of the Public Regulated Service (PRS), that provides highly accurate and robust encrypted signals for authorised governmental users.

The most complex puzzle

“How can we migrate such an extraordinarily complex system without its billions of users noticing?” wondered the ESA Ground Segment team, responsible for the design, management and oversight of the system upgrade. For an answer, they turned to previous experiences and lessons learned, developing a strategy that ensured service continuity at all times. This was made possible by redundant infrastructure and the capability to roll back the migration at any time within the first 48 hours after the switch if necessary.

In the months leading to the upgrade, the teams involved simulated different scenarios, some of which pushed the system to its limits. These exercises were used to validate or update procedures as well as to train the personnel.

The actual migration from the legacy system to a completely new infrastructure, the largest upgrade of a navigation ground segment ever, took less than six weeks. Authorisation to migrate was granted by the EU Space Programme Security Accreditation Board on 1 March, and on 11 March at 13:39 GMT/14:39 CET the first Galileo Navigation Message was disseminated to users from the new Ground Segment version. The upgrade of the Control Centres was successfully completed on 26 March, followed by the upgrade of the Security Monitoring Centres, concluded on 10 April. The new PRS Signal-in-Space was first broadcasted on 12 April.

 “We had some minutes of high pressure at the most critical moment, when switching between versions. Thanks to a smart strategy, preparation, rehearsals and the motivation and competency of everyone involved, we pushed through and succeeded,” declares Sonia Toribio, ESA’s Galileo Ground Segment Manager. “ESA, the EC, EUSPA and our industrial partners were pursuing a single goal: to serve European citizens with the most accurate and robust GNSS.”

The migration did not have any impact on Open Service users and the stability of the Galileo signal broadcast during the migration was excellent. Now the last pieces of the puzzle are being put in place, with uplink and sensor stations joining in the upgrade.

“When you consider the extreme precision in time and position of Galileo and the need for this migration to occur in real-time, the project seemed like a chimera. All teams were ready for any possible contingency during the migration, with very limited windows of opportunity. The result could not be more satisfactory: the seamless transition that was not perceived by any user is a testament of the professionality and knowhow of all teams involved,” states Miguel Manteiga Bautista, ESA Galileo Programme Manager.

What does this upgrade mean for Galileo?

The System Build 2.0 migration is the culmination of years of preparation and a major step forward for European satellite navigation. This upgrade brings enhanced robustness to the Galileo Ground Mission Segment, added security capabilities to Security Operations Centres and reinforced cyber protection. The change also enables the system to grow and accommodate new Galileo architectures brought by Galileo Second Generation.

Ennio Guarino, Head of ESA Galileo and EGNOS Programme Department remarks, “This system upgrade allows Europe to turn the page in the provision of secure and reliable navigation services, keeping Galileo at the forefront of global satellite navigation systems.”

About Galileo

Galileo is currently the world’s most precise satellite navigation system, serving over four billion smartphone users around the globe since entering Open Service in 2017. All smartphones sold in the European Single Market are now guaranteed Galileo-enabled. In addition, Galileo is making a difference across the fields of rail, maritime, agriculture, financial timing services and rescue operations.

A flagship programme of the EU, Galileo is managed and funded by the European Commission. Since its inception, ESA leads the design, development and qualification of the space and ground systems, as well as procuring launches. ESA is also entrusted with research and development activities for the future of Galileo within the EU programme Horizon Europe. The EU Agency for the Space Programme (EUSPA) acts as the service provider, overseeing the market and application needs and closing the loop with users.

For more info about Galileo: https://www.usegalileo.eu/EN/