The "Initial Services" of the Galileo satellite system were successfully restored on July 19, according to the German Aerospace Centre. Since July 11, Europe's satellite navigation system had been partially unavailable to users due to a technical incident in ground-based infrastructure. The European Global Navigation Satellite Systems Agency (GSA) in Prague  informed its customers of the initial failure.

Use at your own risk

During the period of non-service the GSA had warned that there was a "degradation on all Galileo satellites" and that "the signals may not be available nor meet the minimum performance levels" promised by Galileo. Customers who nevertheless continued to use devices that calculated their position using Galileo satellites would do so at their "own risk."

In a further communication on July 14, the GSA added that the cause of the breakdown was to be found in ground-based infrastructure and not in the satellites themselves.

'Search and Rescue' still works

The Search and Rescue (SAR) function, with which ships in distress at sea or injured mountaineers can call for help, continued to function undisturbed, the operating company says.

GSA did not immediately comment on the technical cause of the failure, but the company has set up a an "Anomaly Review Board" to discover the error. 

Read more: Post-Brexit UK won't use EU Galileo satellite system, British PM says

Galileo behind schedule and over budget

For now, the GSA only offers initial services from Galileo, meaning navigation signals come from just 26 satellites. Once a total of 30 Galileo satellites are in their final orbit and fully deployed by 2020, the European satellite navigation system will go into regular operation.

This means the European Union's prestigious project is well behind schedule. Initially, Galileo was supposed to be fully operational by 2008. In terms of costs, the EU was also unable to stick to its original plans. In 1999, it had budgeted between 2.2 and 2.9 billion euros for the construction of the system, whereas the EU budget now provides for 7.2 billion euros to be spent on the construction of the system by 2020 — plus a further 3 billion euros for its operation.

Better plan for redundancy

The new failure highlights the vulnerability and risks of satellite navigation systems. Galileo, and the Global Positioning System (GPS) in the US, both of which are constantly being upgraded, are to assume important tasks in the field of autonomous driving, flying and shipping in the future. However, if autonomous vehicles, aircraft and ships are dependent on only one navigation system at a time, this could lead to a loss of control in the event of a failure.

Many receivers are therefore designed to evaluate signals from several satellite providers, such as Galileo, GPS and Russia's Glonass. More complex systems also use additional locating signals from terrestrial radio systems, such as mobile phone transmitters. This makes them more reliable and less susceptible to interference.

Autonomous vehicles also have radar — and often, additional optical sensors — to ensure that there is no sudden collision in the case of incorrect or missing satellite data.

Read more: Four more Galileo satellites enter space