Galileo Ground Segment - Revision history

Gema.Cueto: Updated GALILEO OS SDD reference link

2026-04-16T13:59:43Z

Updated GALILEO OS SDD reference link

← Older revision		Revision as of 13:59, 16 April 2026
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	The core of the [[GALILEO General Introduction\|GALILEO ]] ground segment are the two Galileo Control Centres (GCC). Each control centre manages ''control'' functions supported by a Galileo Control Segment (GCS) and ''mission'' functions, supported by a dedicated Galileo Mission Segment (GMS): The GCS handles spacecraft housekeeping and constellation maintenance while the GMS handles navigation system control.<ref name="Galileo System">[https://www.gsc-europa.eu/galileo/system Galileo System at European Galileo Service Centre website ]</ref>		The core of the [[GALILEO General Introduction\|GALILEO ]] ground segment are the two Galileo Control Centres (GCC). Each control centre manages ''control'' functions supported by a Galileo Control Segment (GCS) and ''mission'' functions, supported by a dedicated Galileo Mission Segment (GMS): The GCS handles spacecraft housekeeping and constellation maintenance while the GMS handles navigation system control.<ref name="Galileo System">[https://www.gsc-europa.eu/galileo/system Galileo System at European Galileo Service Centre website ]</ref>

	The GCS and GMS interfaces the satellites with a worldwide ground station network implementing control and monitoring functions <ref name="Galileo System">[https://www.gsc-europa.eu/galileo/system Galileo System at European Galileo Service Centre website ]</ref> <ref name="Galileo OS SDD">[https://www.gsc-europa.eu/~~system~~/files/~~galileo_documents~~/Galileo-OS-~~SDD~~.pdf Galileo Open Service - Service Definition Document ]</ref> :		The GCS and GMS interfaces the satellites with a worldwide ground station network implementing control and monitoring functions <ref name="Galileo System">[https://www.gsc-europa.eu/galileo/system Galileo System at European Galileo Service Centre website ]</ref> <ref name="Galileo OS SDD">[https://www.gsc-europa.eu/sites/default/files/sites/all/files/Galileo-OS-SDD_in_force.pdf Galileo Open Service - Service Definition Document ]</ref> :
	* '''Galileo Sensor Stations (GSS)''', responsible for collecting and sending in real time the data measurements of Galileo SIS.		* '''Galileo Sensor Stations (GSS)''', responsible for collecting and sending in real time the data measurements of Galileo SIS.
	* '''Galileo Uplink Stations (ULS)''', responsible for the distribution and uplink of the mission data to the Galileo constellation.		* '''Galileo Uplink Stations (ULS)''', responsible for the distribution and uplink of the mission data to the Galileo constellation.
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	There are several services facilities that complement the core infrastructure <ref name="Galileo System">[https://www.gsc-europa.eu/galileo/system Galileo System at European Galileo Service Centre website ]</ref> <ref name="Galileo OS SDD">[https://www.gsc-europa.eu/~~system~~/files/~~galileo_documents~~/Galileo-OS-~~SDD~~.pdf Galileo Open Service - Service Definition Document ]</ref><ref name="Galileo SAR SDD">[https://www.gsc-europa.eu/sites/default/files/sites/all/files/Galileo-SAR-SDD.pdf Galileo SAR Service Definition Document ]</ref> :		There are several services facilities that complement the core infrastructure <ref name="Galileo System">[https://www.gsc-europa.eu/galileo/system Galileo System at European Galileo Service Centre website ]</ref> <ref name="Galileo OS SDD">[https://www.gsc-europa.eu/sites/default/files/sites/all/files/Galileo-OS-SDD_in_force.pdf Galileo Open Service - Service Definition Document ]</ref><ref name="Galileo SAR SDD">[https://www.gsc-europa.eu/sites/default/files/sites/all/files/Galileo-SAR-SDD.pdf Galileo SAR Service Definition Document ]</ref> :
	*The '''European GNSS Service Centre (GSC)''': located in Torrejón (Spain), the centre represents the link between the Galileo Initial OS (and in the future HAS) user communities and the Galileo system		*The '''European GNSS Service Centre (GSC)''': located in Torrejón (Spain), the centre represents the link between the Galileo Initial OS (and in the future HAS) user communities and the Galileo system
	*The '''Geodetic Reference Service Provider (GRSP)''': responsible for the data processing that sustain the Galileo Control Centres in order to realise the Galileo Terrestrial Reference Frame (GTRF) consistently with the International Terrestrial Reference Frame (ITRF)		*The '''Geodetic Reference Service Provider (GRSP)''': responsible for the data processing that sustain the Galileo Control Centres in order to realise the Galileo Terrestrial Reference Frame (GTRF) consistently with the International Terrestrial Reference Frame (ITRF)

Gema.Cueto at 14:53, 20 October 2022

2022-10-20T14:53:00Z

← Older revision		Revision as of 14:53, 20 October 2022
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	The ground segment also comprises a set of Medium-Earth Orbit Local User Terminals (MEOLUTs) serving Galileo’s Search and Rescue service.		The ground segment also comprises a set of Medium-Earth Orbit Local User Terminals (MEOLUTs) serving Galileo’s Search and Rescue service.

	[[File:~~Galileo_s_Global_Ground_Segment~~.jpg\|left\|400px\|Galileo Ground Segment\|thumb]]		[[File:Galileo_Global_Ground_Segment.jpg\|left\|400px\|Galileo Ground Segment\|thumb]]

Gema.Cueto at 14:40, 20 October 2022

2022-10-20T14:40:21Z

← Older revision		Revision as of 14:40, 20 October 2022
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	*The '''Geodetic Reference Service Provider (GRSP)''': responsible for the data processing that sustain the Galileo Control Centres in order to realise the Galileo Terrestrial Reference Frame (GTRF) consistently with the International Terrestrial Reference Frame (ITRF)		*The '''Geodetic Reference Service Provider (GRSP)''': responsible for the data processing that sustain the Galileo Control Centres in order to realise the Galileo Terrestrial Reference Frame (GTRF) consistently with the International Terrestrial Reference Frame (ITRF)
	*The '''Time Service Provider (TSP)''': supports the GCC by realising the Galileo System Time (GST) in order to make it aligned to the Coordinated Universal Time (UTC).		*The '''Time Service Provider (TSP)''': supports the GCC by realising the Galileo System Time (GST) in order to make it aligned to the Coordinated Universal Time (UTC).
	*The '''Galileo Security Monitoring Centre (GSMC)''': located in St. Germain-en-Laye (France) and ~~Swanwick~~ (~~United Kingdom~~) these facilities are responsible for system security monitoring		*The '''Galileo Security Monitoring Centre (GSMC)''': located in St. Germain-en-Laye (France) and Madrid (Spain) these facilities are responsible for system security monitoring
	*The '''SAR/Galileo Data Service Provider (SGDSP)''': located in Toulouse (France), this entity is responsible of the SAR/Galileo service operations coordination. There is also a MEOLUT Tracking Coordination Facility (MTCF) locate in the SAR/Galileo Service Centre.		*The '''SAR/Galileo Data Service Provider (SGDSP)''': located in Toulouse (France), this entity is responsible of the SAR/Galileo service operations coordination. There is also a MEOLUT Tracking Coordination Facility (MTCF) locate in the SAR/Galileo Service Centre.
	*The '''Galileo Reference Centre (GRC)''': located in Noordwijk (The Netherlands), this facility is in charge of the performance monitoring and assessment of Galileo services. This facility is independent from the Galileo core infrastructure and its operations.[[File:Galileo_Ground_Segment_Architecture.png\|right\|300px\|Galileo Ground Segment Architecture\|thumb]]		*The '''Galileo Reference Centre (GRC)''': located in Noordwijk (The Netherlands), this facility is in charge of the performance monitoring and assessment of Galileo services. This facility is independent from the Galileo core infrastructure and its operations.[[File:Galileo_Ground_Segment_Architecture.png\|right\|300px\|Galileo Ground Segment Architecture\|thumb]]

Gema.Cueto at 10:10, 18 March 2020

2020-03-18T10:10:02Z

← Older revision		Revision as of 10:10, 18 March 2020
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	There are several services facilities that ~~complements~~ the core infrastructure <ref name="Galileo System">[https://www.gsc-europa.eu/galileo/system Galileo System at European Galileo Service Centre website ]</ref> <ref name="Galileo OS SDD">[https://www.gsc-europa.eu/system/files/galileo_documents/Galileo-OS-SDD.pdf Galileo Open Service - Service Definition Document ]</ref><ref name="Galileo SAR SDD">[https://www.gsc-europa.eu/sites/default/files/sites/all/files/Galileo-SAR-SDD.pdf Galileo SAR Service Definition Document ]</ref> :		There are several services facilities that complement the core infrastructure <ref name="Galileo System">[https://www.gsc-europa.eu/galileo/system Galileo System at European Galileo Service Centre website ]</ref> <ref name="Galileo OS SDD">[https://www.gsc-europa.eu/system/files/galileo_documents/Galileo-OS-SDD.pdf Galileo Open Service - Service Definition Document ]</ref><ref name="Galileo SAR SDD">[https://www.gsc-europa.eu/sites/default/files/sites/all/files/Galileo-SAR-SDD.pdf Galileo SAR Service Definition Document ]</ref> :
	*The '''European GNSS Service Centre (GSC)''': located in Torrejón (Spain), the centre represents the link between the Galileo Initial OS (and in the future HAS) user communities and the Galileo system		*The '''European GNSS Service Centre (GSC)''': located in Torrejón (Spain), the centre represents the link between the Galileo Initial OS (and in the future HAS) user communities and the Galileo system
	*The '''Geodetic Reference Service Provider (GRSP)''': responsible of the data processing that sustain the Galileo Control Centres in order to realise the Galileo Terrestrial Reference Frame (GTRF) consistently with the International Terrestrial Reference Frame (ITRF)		*The '''Geodetic Reference Service Provider (GRSP)''': responsible for the data processing that sustain the Galileo Control Centres in order to realise the Galileo Terrestrial Reference Frame (GTRF) consistently with the International Terrestrial Reference Frame (ITRF)
	*The '''Time Service Provider (TSP)''': supports the GCC by realising the Galileo System Time (GST) in order to make it aligned to the Coordinated Universal Time (UTC).		*The '''Time Service Provider (TSP)''': supports the GCC by realising the Galileo System Time (GST) in order to make it aligned to the Coordinated Universal Time (UTC).
	*The '''Galileo Security Monitoring Centre (GSMC)''': located in St. Germain-en-Laye (France) and Swanwick (United Kingdom) these facilities are responsible for system security monitoring		*The '''Galileo Security Monitoring Centre (GSMC)''': located in St. Germain-en-Laye (France) and Swanwick (United Kingdom) these facilities are responsible for system security monitoring

Gema.Cueto at 07:23, 18 March 2020

2020-03-18T07:23:10Z

← Older revision		Revision as of 07:23, 18 March 2020
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	*The '''Time Service Provider (TSP)''': supports the GCC by realising the Galileo System Time (GST) in order to make it aligned to the Coordinated Universal Time (UTC).		*The '''Time Service Provider (TSP)''': supports the GCC by realising the Galileo System Time (GST) in order to make it aligned to the Coordinated Universal Time (UTC).
	*The '''Galileo Security Monitoring Centre (GSMC)''': located in St. Germain-en-Laye (France) and Swanwick (United Kingdom) these facilities are responsible for system security monitoring		*The '''Galileo Security Monitoring Centre (GSMC)''': located in St. Germain-en-Laye (France) and Swanwick (United Kingdom) these facilities are responsible for system security monitoring
	*The '''SAR/Galileo Data Service Provider (SGDSP)''': located in Toulouse (France), this entity is responsible of the SAR/Galileo service operations coordination.		*The '''SAR/Galileo Data Service Provider (SGDSP)''': located in Toulouse (France), this entity is responsible of the SAR/Galileo service operations coordination. There is also a MEOLUT Tracking Coordination Facility (MTCF) locate in the SAR/Galileo Service Centre.
	*The '''Galileo Reference Centre (GRC)''': located in Noordwijk (The Netherlands), this facility is in charge of the performance monitoring and assessment of Galileo services. This facility is independent from the Galileo core infrastructure and its operations.[[File:Galileo_Ground_Segment_Architecture.png\|right\|300px\|Galileo Ground Segment Architecture\|thumb]]		*The '''Galileo Reference Centre (GRC)''': located in Noordwijk (The Netherlands), this facility is in charge of the performance monitoring and assessment of Galileo services. This facility is independent from the Galileo core infrastructure and its operations.[[File:Galileo_Ground_Segment_Architecture.png\|right\|300px\|Galileo Ground Segment Architecture\|thumb]]

Gema.Cueto: /* Galileo Mission Segment (GMS) */

2020-03-17T14:12:09Z

Galileo Mission Segment (GMS)

← Older revision		Revision as of 14:12, 17 March 2020
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	The Galileo Mission Segment (GMS) consists of facilities deployed in the two Galileo Control Centres (GCCs) plus a series of Mission Up-Link Stations (ULS) and Galileo Sensor Stations (GSS) deployed at remote sites located around the world.		The Galileo Mission Segment (GMS) consists of facilities deployed in the two Galileo Control Centres (GCCs) plus a series of Mission Up-Link Stations (ULS) and Galileo Sensor Stations (GSS) deployed at remote sites located around the world.
	The GMS is responsible for the determination and uplink of navigation data messages needed to provide the navigation and timing data. For this purpose, it uses a global network of Galileo Sensor Stations (GSS) ~~<ref name="Galileo System">[https://www.gsc-europa.eu/galileo-gsc-overview/system Galileo System at European Galileo Service Centre website ]</ref>~~ <ref name="Galileo System">[https://www.gsc-europa.eu/galileo/system Galileo System at European Galileo Service Centre website ]</ref> to monitor the navigation signals of all satellites on a continuous basis, through a comprehensive communications network using commercial satellites as well as cable connections in which each link is duplicated for redundancy.		The GMS is responsible for the determination and uplink of navigation data messages needed to provide the navigation and timing data. For this purpose, it uses a global network of Galileo Sensor Stations (GSS) <ref name="Galileo System">[https://www.gsc-europa.eu/galileo/system Galileo System at European Galileo Service Centre website ]</ref> to monitor the navigation signals of all satellites on a continuous basis, through a comprehensive communications network using commercial satellites as well as cable connections in which each link is duplicated for redundancy.

	The GMS communicates with the Galileo satellites through a global network of Mission Up-Link Stations (ULS), installed at five sites, each of which hosts a number of 3-meter antennas. ULSs operate in the 5 GHz Radionavigation Satellite (Earth-to-space) band.		The GMS communicates with the Galileo satellites through a global network of Mission Up-Link Stations (ULS), installed at five sites, each of which hosts a number of 3-meter antennas. ULSs operate in the 5 GHz Radionavigation Satellite (Earth-to-space) band.

Gema.Cueto at 14:11, 17 March 2020

2020-03-17T14:11:40Z

Gema.Cueto at 14:08, 17 March 2020

2020-03-17T14:08:53Z

← Older revision		Revision as of 14:08, 17 March 2020
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	There are several services facilities that complements the core infrastructure <ref name="Galileo System">[https://www.gsc-europa.eu/galileo-gsc-overview/system Galileo System at European Galileo Service Centre website ]</ref> <ref name="Galileo OS SDD">[https://www.gsc-europa.eu/system/files/galileo_documents/Galileo-OS-SDD.pdf Galileo Open Service - Service Definition Document ]</ref><ref name="Galileo SAR SDD">[https://www.gsc-europa.eu/sites/default/files/sites/all/files/Galileo-SAR-SDD.pdf Galileo SAR Service Definition Document ]</ref> :		There are several services facilities that complements the core infrastructure <ref name="Galileo System">[https://www.gsc-europa.eu/galileo-gsc-overview/system Galileo System at European Galileo Service Centre website ]</ref> <ref name="Galileo OS SDD">[https://www.gsc-europa.eu/system/files/galileo_documents/Galileo-OS-SDD.pdf Galileo Open Service - Service Definition Document ]</ref><ref name="Galileo SAR SDD">[https://www.gsc-europa.eu/sites/default/files/sites/all/files/Galileo-SAR-SDD.pdf Galileo SAR Service Definition Document ]</ref> :
	*The '''European GNSS Service Centre (GSC)''': located in Torrejón (Spain), the centre represents the link between the Galileo Initial OS (and in the future HAS) user communities and the Galileo system		*The '''European GNSS Service Centre (GSC)''': located in Torrejón (Spain), the centre represents the link between the Galileo Initial OS (and in the future HAS) user communities and the Galileo system
	*The '''Geodetic Reference Service Provider (GRSP)''': responsible of the data processing that sustain the Galileo Control Centres in order to realise the Galileo Terrestrial Reference Frame (GTRF). consistently with the International Terrestrial Reference Frame (ITRF)		*The '''Geodetic Reference Service Provider (GRSP)''': responsible of the data processing that sustain the Galileo Control Centres in order to realise the Galileo Terrestrial Reference Frame (GTRF) consistently with the International Terrestrial Reference Frame (ITRF)
	*The '''Time Service Provider (TSP)''': supports the GCC by realising the Galileo System Time (GST) in order to make it aligned to the Coordinated Universal Time (UTC).		*The '''Time Service Provider (TSP)''': supports the GCC by realising the Galileo System Time (GST) in order to make it aligned to the Coordinated Universal Time (UTC).
	*The '''Galileo Security Monitoring Centre (GSMC)''': located in St. Germain-en-Laye (France) and Swanwick (United Kingdom) these facilities are responsible for system security monitoring		*The '''Galileo Security Monitoring Centre (GSMC)''': located in St. Germain-en-Laye (France) and Swanwick (United Kingdom) these facilities are responsible for system security monitoring

Gema.Cueto at 14:08, 17 March 2020

2020-03-17T14:08:19Z

← Older revision		Revision as of 14:08, 17 March 2020
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	There are several services facilities that complements the core infrastructure <ref name="Galileo System">[https://www.gsc-europa.eu/galileo-gsc-overview/system Galileo System at European Galileo Service Centre website ]</ref> <ref name="Galileo OS SDD">[https://www.gsc-europa.eu/system/files/galileo_documents/Galileo-OS-SDD.pdf Galileo Open Service - Service Definition Document ]</ref> :		There are several services facilities that complements the core infrastructure <ref name="Galileo System">[https://www.gsc-europa.eu/galileo-gsc-overview/system Galileo System at European Galileo Service Centre website ]</ref> <ref name="Galileo OS SDD">[https://www.gsc-europa.eu/system/files/galileo_documents/Galileo-OS-SDD.pdf Galileo Open Service - Service Definition Document ]</ref><ref name="Galileo SAR SDD">[https://www.gsc-europa.eu/sites/default/files/sites/all/files/Galileo-SAR-SDD.pdf Galileo SAR Service Definition Document ]</ref> :
	*The '''European GNSS Service Centre (GSC)''': located in Torrejón (Spain), the centre represents the link between the Galileo Initial OS (and in the future HAS) user communities and the Galileo system		*The '''European GNSS Service Centre (GSC)''': located in Torrejón (Spain), the centre represents the link between the Galileo Initial OS (and in the future HAS) user communities and the Galileo system
	*The '''Geodetic Reference Service Provider (GRSP)''': responsible of the data processing that sustain the Galileo Control Centres in order to realise the Galileo Terrestrial Reference Frame (GTRF). consistently with the International Terrestrial Reference Frame (ITRF)		*The '''Geodetic Reference Service Provider (GRSP)''': responsible of the data processing that sustain the Galileo Control Centres in order to realise the Galileo Terrestrial Reference Frame (GTRF). consistently with the International Terrestrial Reference Frame (ITRF)

Gema.Cueto at 14:06, 17 March 2020

2020-03-17T14:06:08Z

← Older revision		Revision as of 14:06, 17 March 2020
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	* '''Galileo Uplink Stations (ULS)''', responsible for the distribution and uplink of the mission data to the Galileo constellation.		* '''Galileo Uplink Stations (ULS)''', responsible for the distribution and uplink of the mission data to the Galileo constellation.
	* '''Telemetry, Tracking & Control stations (TT&C)''', responsible for collecting and sending the telemetry data that was generated by the Galileo satellites and also for the distribution and the uplink of the control commands that are necessary to maintain the Galileo satellites and constellation.		* '''Telemetry, Tracking & Control stations (TT&C)''', responsible for collecting and sending the telemetry data that was generated by the Galileo satellites and also for the distribution and the uplink of the control commands that are necessary to maintain the Galileo satellites and constellation.
	The ground segment also comprises a set of ~~four~~ Medium-Earth Orbit Local User Terminals (MEOLUTs) serving Galileo’s Search and Rescue service.		The ground segment also comprises a set of Medium-Earth Orbit Local User Terminals (MEOLUTs) serving Galileo’s Search and Rescue service.

	[[File:Galileo_s_Global_Ground_Segment.jpg\|left\|400px\|Galileo Ground Segment\|thumb]]		[[File:Galileo_s_Global_Ground_Segment.jpg\|left\|400px\|Galileo Ground Segment\|thumb]]

← Older revision		Revision as of 14:11, 17 March 2020
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	The [[GALILEO Ground Segment]] comprises two control centres, a global network of transmitting and receiving stations implementing monitoring and control functions and a series of service facilities which support the provision of the Galileo services.		The [[GALILEO Ground Segment]] comprises two control centres, a global network of transmitting and receiving stations implementing monitoring and control functions and a series of service facilities which support the provision of the Galileo services.

	The core of the [[GALILEO General Introduction\|GALILEO ]] ground segment are the two Galileo Control Centres (GCC). Each control centre manages ''control'' functions supported by a Galileo Control Segment (GCS) and ''mission'' functions, supported by a dedicated Galileo Mission Segment (GMS): The GCS handles spacecraft housekeeping and constellation maintenance while the GMS handles navigation system control.<ref name="Galileo System">[https://www.gsc-europa.eu/galileo~~-gsc-overview~~/system Galileo System at European Galileo Service Centre website ]</ref>		The core of the [[GALILEO General Introduction\|GALILEO ]] ground segment are the two Galileo Control Centres (GCC). Each control centre manages ''control'' functions supported by a Galileo Control Segment (GCS) and ''mission'' functions, supported by a dedicated Galileo Mission Segment (GMS): The GCS handles spacecraft housekeeping and constellation maintenance while the GMS handles navigation system control.<ref name="Galileo System">[https://www.gsc-europa.eu/galileo/system Galileo System at European Galileo Service Centre website ]</ref>

	The GCS and GMS interfaces the satellites with a worldwide ground station network implementing control and monitoring functions <ref name="Galileo System">[https://www.gsc-europa.eu/galileo~~-gsc-overview~~/system Galileo System at European Galileo Service Centre website ]</ref> <ref name="Galileo OS SDD">[https://www.gsc-europa.eu/system/files/galileo_documents/Galileo-OS-SDD.pdf Galileo Open Service - Service Definition Document ]</ref> :		The GCS and GMS interfaces the satellites with a worldwide ground station network implementing control and monitoring functions <ref name="Galileo System">[https://www.gsc-europa.eu/galileo/system Galileo System at European Galileo Service Centre website ]</ref> <ref name="Galileo OS SDD">[https://www.gsc-europa.eu/system/files/galileo_documents/Galileo-OS-SDD.pdf Galileo Open Service - Service Definition Document ]</ref> :
	* '''Galileo Sensor Stations (GSS)''', responsible for collecting and sending in real time the data measurements of Galileo SIS.		* '''Galileo Sensor Stations (GSS)''', responsible for collecting and sending in real time the data measurements of Galileo SIS.
	* '''Galileo Uplink Stations (ULS)''', responsible for the distribution and uplink of the mission data to the Galileo constellation.		* '''Galileo Uplink Stations (ULS)''', responsible for the distribution and uplink of the mission data to the Galileo constellation.
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	There are several services facilities that complements the core infrastructure <ref name="Galileo System">[https://www.gsc-europa.eu/galileo~~-gsc-overview~~/system Galileo System at European Galileo Service Centre website ]</ref> <ref name="Galileo OS SDD">[https://www.gsc-europa.eu/system/files/galileo_documents/Galileo-OS-SDD.pdf Galileo Open Service - Service Definition Document ]</ref><ref name="Galileo SAR SDD">[https://www.gsc-europa.eu/sites/default/files/sites/all/files/Galileo-SAR-SDD.pdf Galileo SAR Service Definition Document ]</ref> :		There are several services facilities that complements the core infrastructure <ref name="Galileo System">[https://www.gsc-europa.eu/galileo/system Galileo System at European Galileo Service Centre website ]</ref> <ref name="Galileo OS SDD">[https://www.gsc-europa.eu/system/files/galileo_documents/Galileo-OS-SDD.pdf Galileo Open Service - Service Definition Document ]</ref><ref name="Galileo SAR SDD">[https://www.gsc-europa.eu/sites/default/files/sites/all/files/Galileo-SAR-SDD.pdf Galileo SAR Service Definition Document ]</ref> :
	*The '''European GNSS Service Centre (GSC)''': located in Torrejón (Spain), the centre represents the link between the Galileo Initial OS (and in the future HAS) user communities and the Galileo system		*The '''European GNSS Service Centre (GSC)''': located in Torrejón (Spain), the centre represents the link between the Galileo Initial OS (and in the future HAS) user communities and the Galileo system
	*The '''Geodetic Reference Service Provider (GRSP)''': responsible of the data processing that sustain the Galileo Control Centres in order to realise the Galileo Terrestrial Reference Frame (GTRF) consistently with the International Terrestrial Reference Frame (ITRF)		*The '''Geodetic Reference Service Provider (GRSP)''': responsible of the data processing that sustain the Galileo Control Centres in order to realise the Galileo Terrestrial Reference Frame (GTRF) consistently with the International Terrestrial Reference Frame (ITRF)
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	The Galileo Mission Segment (GMS) consists of facilities deployed in the two Galileo Control Centres (GCCs) plus a series of Mission Up-Link Stations (ULS) and Galileo Sensor Stations (GSS) deployed at remote sites located around the world.		The Galileo Mission Segment (GMS) consists of facilities deployed in the two Galileo Control Centres (GCCs) plus a series of Mission Up-Link Stations (ULS) and Galileo Sensor Stations (GSS) deployed at remote sites located around the world.
	The GMS is responsible for the determination and uplink of navigation data messages needed to provide the navigation and timing data. For this purpose, it uses a global network of Galileo Sensor Stations (GSS) <ref name="Galileo System">[https://www.gsc-europa.eu/galileo-gsc-overview/system Galileo System at European Galileo Service Centre website ]</ref> <ref name="Galileo ~~OS SDD~~">[https://www.gsc-europa.eu/system~~/files/galileo_documents/~~Galileo~~-OS-SDD.pdf~~ Galileo ~~Open Service -~~ Service ~~Definition Document~~ ]</ref> to monitor the navigation signals of all satellites on a continuous basis, through a comprehensive communications network using commercial satellites as well as cable connections in which each link is duplicated for redundancy.		The GMS is responsible for the determination and uplink of navigation data messages needed to provide the navigation and timing data. For this purpose, it uses a global network of Galileo Sensor Stations (GSS) <ref name="Galileo System">[https://www.gsc-europa.eu/galileo-gsc-overview/system Galileo System at European Galileo Service Centre website ]</ref> <ref name="Galileo System">[https://www.gsc-europa.eu/galileo/system Galileo System at European Galileo Service Centre website ]</ref> to monitor the navigation signals of all satellites on a continuous basis, through a comprehensive communications network using commercial satellites as well as cable connections in which each link is duplicated for redundancy.

	The GMS communicates with the Galileo satellites through a global network of Mission Up-Link Stations (ULS), installed at five sites, each of which hosts a number of 3-meter antennas. ULSs operate in the 5 GHz Radionavigation Satellite (Earth-to-space) band.		The GMS communicates with the Galileo satellites through a global network of Mission Up-Link Stations (ULS), installed at five sites, each of which hosts a number of 3-meter antennas. ULSs operate in the 5 GHz Radionavigation Satellite (Earth-to-space) band.