NAGU Definition
The Notice Advisory to Galileo Users (NAGU) aims to inform about any activity/event in the Galileo system with impact on the Signal in Space (SiS) and/or on the performance levels for Open Service (OS), High Accuracy Service (HAS) and Open Service Navigation Message Authentication (OSNMA) as committed in the applicable Open Service-Service Definition Document, HAS Service Definition Document and OSNMA Service Definition Document respectively.
NAGU Categories
- Planned: all activities/events that have been scheduled and that could potentially have an impact on the service and/or the performance levels. Planned NAGUs aim to inform users about the activity/event with a reasonable advance notice, ahead of their occurrence.
Unplanned: all activities/events that have an impact on the service and/or the performance levels that have not been scheduled and could not be foreseen in advance, before their occurrence. The aim of unplanned NAGUs is to inform users about the activity/event within a reasonable time, after their occurrence.
NAGU Types and Format
There are different NAGU types defined within each NAGU category:
Graphical summary of the OS NAGU types
Graphical summary of the HAS NAGU types
Graphical summary of the OSNMA NAGU types
The following table explains the NAGU types currently in use:
| NAGU Type | NAGU Type (abbreviation) | NAGU Description | NAGU Format |
|---|---|---|---|
PLANNED MANOEUVRE | PLN_MANV | Planned activity affecting the attitude and/or orbit (e.g. Station Keeping Manoeuvre, satellite relocation to a new slot).
| |
PLANNED OUTAGE | PLN_OUTAGE | Planned activity (related to the space and/or the ground segment) that potentially causes an outage of the satellite broadcast SIS (e.g.: on‑board Clock switch, as foreseen by manufacturer for regular equipment maintenance).
| |
CANCELLATION | CANCEL | Cancellation of published NAGU (e.g. due to the withdrawal of planned manoeuvre) | |
RESCHEDULE | RESCH | Provision of new start/end times for an already published NAGU of “PLANNED” category. | |
EXTENSION | EXTNS | Provision of a new end time for any already published NAGU of “PLANNED” category, or notification of the planned outage end time for the published NAGU of “UNPLANNED” category: UNP_UNUFN. | |
SATELLITE DECOMMISSIONED | DECOMMSNG | Commencement of decommissioning phase.
| |
| START OF THE EXTENDED OPERATION MODE | EOM_START | Start time of the Galileo Extended Operation Mode is communicated through this NAGU. | |
| END OF THE EXTENDED OPERATION MODE | EOM_END | Upon recovery of the nominal operation mode, this NAGU is issued to communicate the end time of the Galileo Extended Operation Mode. | |
UNAVAILABLE UNTIL FURTHER NOTICE | UNP_UNUFN
| Unscheduled outage of the broadcast satellite Signal in Space, characterised by an undefined duration. | |
SHORT TERM OUTAGE RECOVERED | UNP_SHTRCVR | Outage events that have been already recovered, before a dedicated NAGU could be published to notify their occurrence. | |
SATELLITE FIRST TIME USABLE | USABINIT | Announces that a given satellite enters its active service provision, contributing to the constellation service delivery.
| |
USABLE FOR SERVICE PROVISION | USABLE | The satellite restarts transmitting healthy Signal in Space, concluding a planned outage period or the recovery after an unplanned outage. | |
GENERAL NOTICE FOR UNPLANNED EVENTS | GENERAL (NOTICE) | This NAGU type provides general notifications announcing unplanned events such as “Service accuracy degradations”. | |
GENERAL NOTICE FOR PLANNED EVENTS | GENERAL (NOTICE) | This NAGU type provides general notifications announcing planned events such as “Galileo Initial Open Service (OS) declaration”, “System evolution activity”. | |
LAUNCH | LAUNCH | This NAGU provides notification of Galileo satellite(s) launch event. |
|
LEAP SECOND | LEAP SECOND | This NAGU provides notification of a leap second adjustment affecting UTC time scale, following the related announcement by IERS. | |
PLANNED OUTAGE TIMING SERVICES | TIMING PLN_OUTAGE (GGTO, GST-UTC) | This NAGU provides notification of a planned operation entailing a maintenance of timing related services (GGTO, GST-UTC). | |
AVAILABILITY OF THE GST-UTC TIMING SERVICE | TIMING USABLE (GST-UTC) | Notification of availability of the GST-UTC timing service following the end of a planned operation / recovery of an unplanned timing outage. | |
AVAILABILITY OF THE GGTO TIMING SERVICE | TIMING USABLE (GGTO) | Notification of availability of the GGTO timing service following the end of a planned operation / recovery of an unplanned timing outage. | |
CANCELLATION OF PLANNED OUTAGE TIMING SERVICES | TIMING CANCEL | Cancellation of a published NAGU notification addressing a planned operation entailing an outage only affecting the timing services (GGTO, GST-UTC). | |
RESCHEDULE OF PLANNED OUTAGE TIMING SERVICES | TIMING RESCH | Provision of new start/end times for published NAGU addressing a planned operation entailing an outage only affecting the timing services (GGTO, GST-UTC). | |
EXTENSION OF PLANNED OUTAGE TIMING SERVICES | TIMING EXTNS | Provision of new end time for a published, PLANNED NAGU entailing an outage only affecting the timing services (GGTO, GST-UTC) | |
UNPLANNED OUTAGE GST-UTC TIMING SERVICE | TIMING UNP_UNUFN (GST-UTC) | Unplanned GST-UTC timing service outage. | |
UNPLANNED OUTAGE GGTO TIMING SERVICE | TIMING UNP_UNUFN (GGTO) | Unplanned GGTO timing service outage. | |
SHORT TERM OUTAGE GST-UTC TIMING SERVICE | TIMING UNP_SHTRCVR (GST-UTC) | Communication of the recovery of short-term GST-UTC timing service outage. | |
SHORT TERM OUTAGE GGTO TIMING SERVICE | TIMING UNP_SHTRCVR (GGTO) | Communication of the recovery of short-term GGTO timing service outage. | |
HAS GENERAL NOTICE FOR PLANNED/UNPLANNED EVENTS | HAS GENERAL (NOTICE) | This NAGU type provides general notifications about general HAS events, e.g., announcement of “HAS Enhanced Service declaration”, “HAS service degradations”, etc. | |
| PLANNED OUTAGE HAS SERVICES | HAS PLN_OUTAGE | This NAGU provides A HAS outage consists of the complete absence of valid HAS orbit and/or clock corrections for all satellites in the HAS SIS (C/NAV message). | |
| AVAILABILITY OF HAS | HAS USABLE | This NAGU provides | |
| CANCELLATION OF PLANNED OUTAGE HAS | HAS CANCEL | Cancellation of a published NAGU notification for a planned operation, entailing an outage affecting the High Accuracy Service. | |
| RESCHEDULE OF PLANNED OUTAGE HAS | HAS RESCH | Provision of new start/end times for a published NAGU notification for a planned operation, entailing an outage affecting the High Accuracy Service. | |
| EXTENSION OF PLANNED OUTAGE HAS | HAS EXTNS | Provision of new end time for a published, planned NAGU entailing an outage affecting the High Accuracy Service. | |
| UNPLANNED OUTAGE HAS | HAS UNP_UNUFN | This NAGU provides | |
| SHORT TERM OUTAGE HAS | HAS UNP_SHTRCVR | This NAGU provides | |
| OSNMA GENERAL NOTICE FOR PLANNED/UNPLANNED EVENTS | OSNMA GENERAL (NOTICE) | This NAGU type provides notifications about general OSNMA events, e.g., announcement of “OSNMA Enhanced Service declaration”, “OSNMA service degradations”, etc. Depending on the nature of the general event, it will be communicated either before or after its occurrence. | |
OSNMA PUBLIC KEY RENEWAL | OSNMA PK_RENEWAL | An OSNMA Public Key renewal will take place. | |
OSNMA TESLA CHAIN RENEWAL | OSNMA TESLA_CHAIN_RENEWAL | An OSNMA TESLA Chain renewal will take place. | |
OSNMA MERKLE TREE RENEWAL | OSNMA MT_RENEWAL | An OSNMA Merkle Tree renewal will take place. | |
OSNMA PLANNED OUTAGE | OSNMA PLN_OUTAGE | A planned operation affecting the OSNMA service provision will take place. | |
OSNMA PUBLIC KEY REVOCATION | OSNMA PK_REVOCATION | An OSNMA Public Key revocation took place. | |
OSNMA TESLA CHAIN REVOCATION | OSNMA TESLA_CHAIN_REVOCATION | An OSNMA TESLA Chain revocation took place. | |
OSNMA ALERT MESSAGE | OSNMA ALERT_MESSAGE | OSNMA Alert Message was broadcast. | |
OSNMA UNPLANNED OUTAGE UNTIL FURTHER NOTICE | OSNMA UNP_UNUFN | An unplanned outage affecting the OSNMA service provision took place. | |
OSNMA UNPLANNED SHORT RECOVERY | OSNMA UNP_SHTRCVR | An unplanned event, that caused an OSNMA outage, that has been already recovered before a dedicated NAGU could be published | |
OSNMA CANCELLATION | OSNMA CANCEL | Cancellation of published OSNMA NAGU (e.g., due to the withdrawal of a planned outage). | |
OSNMA RESCHEDULE | OSNMA RESCH | Provision of new start/end times for an already published PLANNED OSNMA NAGU. | |
OSNMA EXTENSION | OSNMA EXTNS | Provision of a new end time for an already published PLANNED OSNMA NAGU. | |
OSNMA USABLE | OSNMA USABLE | The OSNMA service is restored after an Alert Message broadcast or a planned/unplanned outage |
The following table shows the NAGU types that were used in the past (e.g., prior to declaration of OS Initial Services) and are not currently in use:
| NAGU Type | NAGU Type (abbreviation) | NAGU Description |
|---|---|---|
SATELLITE FIRST TIME AVAILABLE | AVAILINIT | Satellite first time available. This NAGU type was used prior to the OS Initial Services Declaration. As of 15th of December, 2016, the OS Initial Services Declaration has taken place and USABINIT NAGU will be published instead of AVAILINIT NAGU. |
AVAILABLE FOR TESTING | AVAILABLE | Satellite available for testing purposes. This NAGU type was used prior to the Initial Services Declaration. As of 15th of December, 2016, the OS Initial Services Declaration has taken place and USABLE NAGU will be published instead of AVAILABLE NAGU. |
PLANNED UNAVAILABLE UNTIL FURTHER NOTICE | PLN_UNUFN | All planned outages are notified via PLN_OUTAGE. |
SATELLITE UNDER COMMISSIONING | COMMSNG | Superseded by the information provided by the prevision of the scope of the GENERAL NAGU announcing the launch of the satellite. |
DEFINITION OF NAGU FIELDS
Header: the first line of the text field includes the title “NOTICE ADVISORY TO GALILEO USERS (NAGU)”, which is followed by the NAGU SPECIFIC number given in the format YYYYNNN, where YYYY is the Gregorian year and NNN is the sequential number of NAGU, starting with 001 on the 1st of January every year and incrementing by 1 at each subsequent NAGU.
Date generated (UTC): the second line contains the date at which the NAGU was generated on the GSC website, in UTC time scale, format YYYY-MM-DD hh:mm where YYYY is the Gregorian year, MM is the number of the month from 1-12 in sequence starting with 1 being January and finishing with 12 being December, DD is the day within the Gregorian month, hh is the hour in the 24 hour format and mm is the minute.
NAGU type: as per NAGU definition. See NAGU types table in the section above.
NAGU number: this is defined in the format YYYYNNN (previously defined).
NAGU subject: subject of the NAGU summarizing the information provided in the “Event Description”. The text to be used in the subject is defined by the template of each NAGU.
NAGU referenced to: if the current NAGU refers to previous NAGU then the previous NAGU will be in this field in the form of YYYYRRR where YYYY is the Gregorian year the NAGU was issued and RRR is the number of the NAGU for that year. If there is no reference to previous NAGU then “N/A” (not applicable) will appear here instead.
Start date event (UTC): the start date of the event notified in this NAGU in the UTC time scale with format YYYY-MM-DD hh:mm (see the definition of time in “2.” above).
End date event (UTC): the end date of the event notified in this NAGU in UTC time scale with format YYYY-MM-DD hh:mm (see the definition of time in “2.” above).
Satellite affected: GSAT (Galileo SATellite) name of the satellite affected.
Space vehicle ID: SVID of the satellite affected. This field is not present in the GENERAL NAGU.
Signal(s) affected: the signal(s) affected by the satellite referenced in the NAGU. The signals affected will be contained within a bracket after the word SIGNAL and can be one or a combination of the following: E1, E5a, E5b, E6-B, E6-C or ALL. Partial outage/availability of the signals is indicated in the NAGU subject if ALL signals are not affected. This field is not present in the GENERAL NAGU.
Signal(s) affected: the signal(s) affected by the satellite referenced in the NAGU. The signals affected will be contained within a bracket after the word SIGNAL and can be one or a combination of the following: E1, E5a, E5b, E6-B, E6-C, ALL. Partial outage/availability of the signals is indicated in the NAGU subject if ALL signals are not affected.
Event description: the event description following the templates defined for each NAGU.
NAGU Timeliness
The timely publication of NAGUs refers to the time intervals within which Galileo NAGUs are published before any planned event or after any unplanned event. The minimum performance level for the timely publication of NAGUs is specified in the applicable Open Service-Service Definition Document (OS-SDD), High Accuracy Service-Service Definition Document (HAS-SDD), Open Service Navigation Message and Authentication-Service Definition Document (OSNMA-SDD).