The entire Galileo system suffered an unexpected and hitherto unexplained signal outage, beginning on Thursday, July 11, at 1 p.m. Central European Time. At about that time, users noticed that all ephemeris stopped broadcasting, and then a Notice Advice to Galileo Users (NAGU) appeared:

NAGU Subject: Service Degradation

Satellite Affected: ALL

Event Description: Until further notices, users may experience service degradation on all Galileo satellites.s this means that the signals may not be available nor meet the minimum performance levels defined in the service definition documents and should be employed at users’ own risk. The nominal service will be resumed as soon as possible.”

The signal outage has persisted for more than two days (as of Saturday) and as yet no word has emerged as to the cause or duration of the signal outage.

On the evening of July 13, a second NAGU appeared, saying simply that “Until further notice, users experience a service outage. the signals are not to be used.”

On the European GNSS Service Centre’s constellation status page , 22 Galileo satellites are listed as “Not Usable” with cause being “Service Outage.”

[Photo: Galileo Control Center, Oberpfaffenhofen. Photo: GSA]