European GNSS Service Centre Started Issueing NAGUs
On June 18, 2013 the European GNSS Service Centre issued the first “NOTICE ADVISORY TO GALILEO USERS” (NAGU). With the NAGUs the Galileo System moves toward a more operational service. The availability of Galileo satellites is becoming predictable since test phases and changes of the constellation may be announced in advance.
The Galileo NAGU service is similar to the GPS NANU and GLONASS NAGU services already established for many years. In their beginnings these services were very important information for all users relying on GPS respectively GLONASS availability. Nowadays the users have an alternative system and the importance of the information in advance is not really significant anymore. Nevertheless, the NANUs and NAGUs provide also an archive for checks of the special constellation conditions.
Typically for GPS NANUs and GLONASS NAGUs an advanced notice with a time schedule is given at least a couple of days prior to a planned event (e.g. maintenance period of a satellite, changes of codes, etc.). When the event occurs a more precise timing is given at its start and at its ending. For Galileo NAGUs the first issues are post event only, but the last 8 (out of 10) NAGUs announced already events prior to their occurrences.