The European Agency for Global Navigation Satellite Systems announces that the problem was a malfunction of equipment in ground control centers that provide forecasts of time and orbit for satellites.
Since December 2016, Galileo is in a pilot phase. Devices that use its signal should be able to switch to GPS or Glonass, the Russian satellite navigation system.
It should become fully operational next year. Thus, it will offer a European civil alternative to American and Russian networks.