NAGUs (Notice Advisory to Galileo Users)

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 as committed in the applicable Open Service-Service Definition Document.

NAGU Categories

  • Planned: all activities/events that have been scheduled and that could potentially have an impact on the SiS 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 SiS 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.

  • Service Availability: all events related to the restoration of service provision, following the end of a planned outage or the recovery of an unplanned outage.

  • General: all activities performed on the Galileo system, or any occurring events, that potentially or substantially have an impact on the SiS and/or on the performance levels, which would not be already covered by a planned or an unplanned NAGU.

NAGU Types and Format

There are different NAGU types defined within each NAGU category:

 

 

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., satellite relocation to a new slot). It includes the planned outage start time and end time.

Template

PLANNED OUTAGE

PLN_OUTAGE

Planned activity, in space or ground segment, that can potentially cause an outage of the broadcast satellite Signal in Space. It includes the planned outage start time and end time.

Template

CANCELLATION

CANCEL

Cancellation of published NAGUs.

Template

RESCHEDULE

RESCH

Provision of new start/end times for an already published NAGU of the “PLANNED” category.

Template

EXTENSION

EXTNS

Provision of new end time for an already published NAGU of the “PLANNED” category, or notification of the planned outage end time for a published NAGU of the “UNPLANNED” category (UNP_UNUFN).

Template

SATELLITE DECOMMISSIONED

DECOMMSNG

Beginning of decommissioning phase. The end time for the nominal provision of service is specified.

Template

UNAVAILABLE UNTIL FURTHER NOTICE

UNP_UNUFN

 

Unscheduled outage of the broadcast satellite Signal in Space, characterised by an undefined duration.

Template

SHORT TERM OUTAGE RECOVERED

UNP_SHTRCVR

Outage events that have been already recovered, before a dedicated NAGU could be published to notify their occurrence.

Template

SATELLITE FIRST TIME USABLE

USABINIT

Satellite enters its active service provision, contributing to the constellation service delivery.
It is used for satellites that enter their service provision for the first time, indicating that the space vehicle is providing a Signal In Space in line with the applicable OS SIS ICD, as well as the published OS SDD and the related service performance commitment.
It includes also the type of clock being used to drive the navigation payload.

Template

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.
It includes also a reminder about the exact outage start time, along with the precise outage end time.
It includes also the type of clock being used to drive the navigation payload.
This NAGU type is also used following Service Declaration, in order to recall the list of space vehicles that are expected to broadcast a Signal in Space aligned with the applicable OS SDD during the specified service provision phase.

Template

GENERAL NOTICE

GENERAL (NOTICE)

General notifications such as: the announcement of the IOV campaign for a given satellite; the validation of a specific service provision phase (e.g., Initial Services, Enhanced Services); the declaration of a specific service provision phase; the introduction of new services; the achievement of a given constellation configuration (e.g., IOC, FOC, etc.).

Template

LAUNCH

GENERAL (LAUNCH)

Notification of Galileo satellite(s) launch event.

Template - 2 satellites

Template - 4 satellites

LEAP SECOND

GENERAL (LEAP SECOND)

Notification of a leap second adjustment affecting UTC time scale, following the related announcement by IERS.

Template

PLANNED OUTAGE TIMING SERVICES

GENERAL (TIMING PLN_OUTAGE)

Notification of a planned operation entailing an outage of timing related services, consisting of GGTO and UTC determination capabilities at user level.

Template

AVAILABILITY OF TIMING SERVICES

GENERAL (TIMING USABLE)

This general NAGU provides notification of availability of timing services following the end of a planned operation or the recovery of an unplanned outage, with an impact only affecting the timing services.

Template

CANCELLATION OF PLANNED OUTAGE TIMING SERVICES

GENERAL (TIMING  CANCEL)

Cancellation of a published general NAGU notification related to a planned operation, entailing an outage only affecting the timing services.

Template

RESCHEDULE OF PLANNED OUTAGE TIMING SERVICES

GENERAL (TIMING  RESCH)

Provision of new start/end times for a published GENERAL NAGU notification related to a planned operation, entailing an outage only affecting the timing services.

Template

EXTENSION OF PLANNED OUTAGE TIMING SERVICES

GENERAL (TIMING  EXTNS)

Provision of new end time for a published GENERAL NAGU notification related to a planned operation, entailing an outage only affecting the timing services.

Template

UNPLANNED OUTAGE TIMING SERVICES

GENERAL (TIMING UNP_UNUFN)

This general NAGU provides notification of an unplanned outage related to timing services.

Template

SHORT TERM OUTAGE TIMING SERVICES

GENERAL (TIMING UNP_SHTRCVR)

This general NAGU provides notification of a short-term timing services outage event that has been already recovered, before a dedicated NAGU could be published to announce its occurrence.

Template

 

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

PLANNED UNAVAILABLE UNTIL FURTHER NOTICE

PLN_UNUFN

Planned outage whose end date is not indicated. This NAGU is no longer used because all planned outages will be notified via PLN_OUTAGE.

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.

SATELLITE UNDER COMMISSIONING

COMMSNG

Satellite under commissioning. This NAGU is no longer used, because it is superseded by the information provided by the GENERAL LAUNCH NAGU, announcing the launch of the satellite.

DEFINITION OF NAGU FIELDS

  1. 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.

  2. 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.

  3. NAGU type: as per NAGU definition. See NAGU types table in the section above.

  4. NAGU number:  this is defined in the format YYYYNNN (previously defined).

  5. 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.

  6. 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.

  7. 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).

  8. 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).

  9. Satellite affected: GSAT (Galileo SATellite) name of the satellite affected.

  10. Space vehicle ID: SVID of the satellite affected.

  11. 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.

  12. 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.