What is Galileo?

Galileo is the EU’s Global Satellite Navigation System (GNSS). Like other global systems, Galileo provides radio signals for position, navigation and timing purposes. Galileo offers several high-performance services worldwide: Open Service, Public Regulated Service, Search and Rescue Service, High Accuracy Service and soon Open Service Navigation Message Authentication,  Emergency Warning Satellite Service, and Commercial Authentication Service. 

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What does Galileo consist of?

The Galileo system is comprised of three segments:

  1. Space Segment

A constellation of satellites transmitting navigation signals as specified in the different Galileo SIS ICDs, providing user access to the Galileo services. The baseline constellation configuration is defined as 24/3/1 Walker constellation: 24 nominal Medium Earth Orbit satellites are arranged in three orbital planes.

  1. Ground Segment

The Galileo Ground Segment includes both the Ground Control Segment (GCS) and the Ground Mission Segment (GMS) encompassing the following infrastructure:

  • Two Galileo Control Centres (GCC)
  • A worldwide network of Galileo Sensor Stations (GSS)
  • A worldwide network of Galileo Uplink Stations (ULS)
  • A worldwide network of Telemetry, Tracking & Control stations (TTC stations)

The core infrastructure is complemented by the Service Facilities supporting the Galileo services provision:

  • The European GNSS Service Centre (GSC)
  • The Geodetic Reference Service Provider (GRSP)
  • The Time Service Provider (TSP)
  • The Galileo Security Monitoring Centre (GSMC)
  • SAR/Galileo Data Service Provider (SGDSP)
  • Galileo Reference Centre (GRC)
  1. User Segment

Different GNSS receivers and devices that receive the Galileo signal-in-space (SiS).


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Who is involved in Galileo?

Galileo is a joint initiative of the European Commission, EUSPA and ESA.

The Galileo programme is owned by the EU. The European Commission has overall responsibility for the programme, managing and overseeing the implementation of all activities on behalf of the EU.

The Commission has delegated the operational management of the programme to EUSPA, which is responsible for the deployment, maintenance and minor evolutions of Galileo system, and that oversees how the Galileo infrastructure is used ensuring that Galileo services are delivered with the defined performance and without interruption.

Galileo's design and system evolution, along with the technical development of its infrastructure, are entrusted to ESA.

Who operates Galileo?

While the European Commission is ultimately responsible for the Galileo programme, EUSPA is responsible for deploying the system and providing technical support for operational tasks, in addition to overseeing its service provision and market development.

In this way, EUSPA serves as the link between the satellites in space and the end user on Earth.

What is the added value of Galileo with respect to other GNSS programmes?

Only the EU has a global civil-based GNSS initiative. The fact that Galileo is under civilian control is an important differentiator from other GNSS systems and is especially relevant when considering that the world’s dependence on GNSS is continuously increasing.

With Galileo, there are more usable GNSS satellites, meaning users around the world have access to more accurate and reliable positioning and timing synchronisation. This is especially relevant in higher latitudes where Galileo offers better coverage than other GNSS systems.

In addition, Galileo offers other added value services devoted to improving performance at the user level:

  • Positioning accuracy down to decimetre level
  • Robust positioning through the authentication of the navigation data
  • Resistance to interference (jamming and spoofing) and high resilience
  • The return link for Search and Rescue operations

Is Galileo free?

All the Galileo services provided to date are free of charge.

How many satellites will Galileo have?

Once the Galileo constellation reaches Full Operational Capability (FOC) it will consist of 24 operational satellites contributing to the achievement of the committed service performance as per OS SDD

The constellation may be complemented by auxiliary satellites that can be repositioned to any given slot in the same plane depending on maintenance or service evolution needs, ensuring the long term availability and, when active, contributing to the performance experienced by the user. From most locations, six to eight satellites are always visible, allowing positions and timing to be determined very accurately to. Interoperability with other GNSS increases the reliability of Galileo services.


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How is Galileo performing?

Galileo’s performance has been excellent! Since the launch of Initial Services, the measured Galileo Open Service and Search and Rescue Service performance figures have comfortably exceeded the Minimum Performance Level thresholds set down in their respective Service Definition Documents. It is important to note that the OS performance is excellent not only with respect to the Galileo MPLs but also with respect to the performance other GNSS

Since the Galileo High Accuracy Initial Service declaration in January 2023,  HAS performance figures are also being reported and compliance with the Minimum Performance Level thresholds is achieved with considerable margins.

To keep you up to date on Galileo’s performance, the European GNSS Service Centre (GSC) issues quarterly reports on Galileo OS, SAR and HAS performance.

What are the expected performances of Galileo once fully deployed?

Expected performances of Galileo once Full Operational Capability is reached can be found in Annex D of the Open Service-Service Definition Document (OS SDD). In this section, the performance evolution is shown including Full Operational Capability with 24 satellites.

Is Galileo compatible with GPS?

Galileo is fully interoperable with GPS, and with other GNSS programmes. The combined use of Galileo and other GNSS brings many benefits to the end user. 

Galileo supports an enhanced level of interoperability with GPS thanks to the broadcast of a specific parameter (the Galileo to GPS Time Offset) that simplify the combined exploitation by Galileo receivers of the two constellations. The concurrent use of various GNSS offers more accurate and reliable positioning and timing synchronisation for end users. Navigation in cities or in complex environments, where satellite signals can often be blocked by buildings, tunnels or cut-offs, particularly benefit from the higher number of satellites in view.

Galileo's accurate timing capability also helps enable more robust, reliable, efficient and resilient synchronisation for critical use domains as banking and financial transactions, telecommunication and energy distribution networks.

What is multi-constellation capacity?

Galileo is interoperable with other GNSS programmes, including GPS (USA), GLONASS (Russia) and BeiDou (China). Receivers with multi-constellation capacity can combine signals from different constellations to provide greater positioning accuracy. Galileo supports an enhanced level of interoperability with GPS thanks to the broadcast of a specific parameter (the Galileo to GPS Time Offset) that simplify the combined exploitation by Galileo receivers of the two constellations.

To further increase the level of Galileo integration, EUSPA works directly with chipset and receiver manufacturers through technology workshops, sharing Galileo updates, co-marketing efforts and dedicated funding for receiver development projects and studies.

Can you use satellite navigation indoors?

Galileo significantly improves accuracy in challenging environments, including urban canyons and indoors, especially when used in combination with other GNSS. In combination with other networks, 5G for example, Galileo provides the accuracy, ubiquity and security needed to support seamless indoor-outdoor navigation solutions.

Who can I contact for more information about Galileo and its services?

The European GNSS Service Centre (GSC) is available to help all Galileo users. The GSC Helpdesk can be reached at http://www.gsc-europa.eu.

What is the Galileo Open Service?

The Galileo Open Service (OS) is a free of charge global ranging, positioning and timing service. Since 2016, Galileo OS provides Europe and European citizens with independence and sovereignty in the provision of positioning service. The Galileo Open Service can be used by the Galileo enabled chipsets found in devices such as smartphones, smartwatch and car navigation systems.

All the details about the Galileo Services performance can be found in the regular reports published on the web site of the GNSS Service Centre, where users can also find the Galileo Open Service – Service Definition Document (OS SDD), which defines the minimum performance provided by the service.

What is the Galileo Public Regulated Service?

The Public Regulated Service (PRS) is for government authorised users, including civil protection units, fire brigades, customs officers and the police. It is particularly robust and fully encrypted to provide service continuity in national emergencies and crisis situations, such as terrorist attacks. 

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What is the Galileo Search and Rescue Service?

The Galileo Search and Rescue (SAR) service is Europe's contribution to an international emergency beacon locating system called "Cospas-Sarsat". Galileo is the largest L-band SAR satellite and ground segment contributor significantly reducing the time needed to accurately locate a distress beacon. Galileo SAR also offers a unique capability called the Return Link that lets users know that their distress signal has been received and the relevant SAR authorities have been notified.

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What is the Galileo High Accuracy Service?

The High Accuracy Service (HAS) is a free high-accuracy positioning service for applications requiring higher accuracy than that offered by the Galileo Open Service. The Galileo High Accuracy Service (HAS) provides precise corrections in the Galileo E6-B data component as well as by terrestrial means so Galileo and GPS (single and multi-frequency) can achieve real-time improved user positioning performances (positioning error of less than two decimetres in nominal conditions).

Learn more on Galileo Services   For more FAQs on HAS, click here

What is Galileo Emergency Warning Satellite Service?

The Galileo Emergency Warning Satellite Service (EWSS) swiftly broadcasts alerts globally, allowing national  civil protection authorities to directly transmit to smartphones (or any Galileo-enabled devices) for enhanced emergency response and resilient risk management.

What is Galileo OSNMA?

Galileo Open Service Navigation Message Authentication (OSNMA) is a free authentication service, available worldwide to allow users to verify whether the navigation message is received by a genuine Galileo satellite. Authentication information is provided through the E1-B component.

What is Commercial Authentication Service?

Commercial Authentication service (CAS) is understood as the ability to provide a level of guarantee to users regarding the use of signals and data from actual Galileo satellites and not from any other source. This capacity will increase the degree of trust on the services based on Galileo positioning and prevent spoofing of Galileo signals, which may lead to committing fraud. The purpose of this service is to satisfy the demand of GNSS users and applications of a trusted navigation solution provided by GNSS systems.

Where can I find official Galileo programme documentation?

All official programme documentation related to Galileo is published in the programme reference documentation section on the GSC website.

What is the status of the Galileo services?

Since 2016, Galileo Open Service, Search and Rescue and Public Regulated Service are being delivered in their initial configuration and users around the world with Galileo enabled devices are being guided with positioning, navigation and timing information provided by Galileo. In parallel, the full infrastructure and system are being deployed, continuously improving the performance of the service and the robustness of the system. 

Technical updates of the Galileo SDDs, integrating the benefits from the subsequent system infrastructure releases are published regularly.

With the declaration of Galileo HAS Initial Service on 24 January 2023, users within the service area can achieve improved user positioning performance in real-time by exploiting the HAS data delivered in the Galileo E6-B signal component and via internet.

Click here to find out if your device is Galileo-enabled.

Are there multi-constellation receivers capable of using GPS, Galileo, Glonass and others?

Chipset and receiver manufacturers are already equipping their devices with multi-constellation capabilities, including Galileo, and taking advantage of all available services.

Can I use Galileo on my mobile phone?

There are already over 2.85 billion Galileo-enabled smartphones in use at the end of 2022 and this number is still growing, as the vast majority of new smartphone models usually have Galileo inside.

Will Galileo satellites track my phone?

Your phone calculates its position by combining signals from navigation satellites. These satellites only send out the signal to your phone but cannot track it.

However, some applications on your phone, such as ride sharing or mapping services, share your location with the application provider. This is done using your internet connection.

Your phone cannot send its location, or any other data for that matter, back to the satellites. The only devices that can send location data back to Galileo satellites are emergency beacons.

Can I use Galileo in my car?

Galileo-enabled navigation devices for your car are already available. What’s more, since 2018, all new type approved vehicles sold in Europe are Galileo capable as part of a requirement to comply with the EU’s eCall emergency response system regulation.

Can I use Galileo enabled devices in other regions of the world?

Yes, Galileo’s services are available worldwide with no restrictions on the use of its signal in any place on the planet (unless local governments prohibit access to specific services).

EUSPA works with other countries and GNSS systems to enable and harmonise the Galileo services provision. For instance, the U.S. Federal Communications Commission (FCC) granted access to specific signals transmitted by Galileo in all the devices in the U.S.

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Why does Europe need Galileo?

Space is big business. What’s more, as of 2023, global revenues from GNSS stood at approximately €260 billion. Projections for 2033 signal significant growth, with GNSS expected to reach €580 billion.

With its own GNSS system, Europe is at the forefront of these developments. The European research and development and industrial sectors are able to leverage Galileo’s services  and features not provided by any other GNSS (such as High Accuracy Service or Search and Rescue service`s Return Link) in countless products and services, creating added value for the European economy and improving the lives of European citizens. Open Service Navigation Message Authentication is already available in numerous market-ready prototypes and will soon be enabled in GNSS receivers allowing to make the PVT solution more robust against data-level spoofing attacks.

Moreover, unlike other GNSS, Galileo is a civilian system. This is an important distinction, especially as our dependence on GNSS continues to increase.

What is the socio-economic impact of Galileo?

Users benefit from more reliable and accurate positioning that aids their navigation, especially in cities and built-up areas. Features like the Galileo Search and Rescue Service and integration into the eCall system reduce emergency service response time in the case of distress or accidents.

Galileo's accurate timing also helps make the synchronisation of banking and financial transactions more resilient, as well as those used by the telecommunication and energy distribution networks that power the global economy.

Galileo’s services are also critical in the fight against climate change and are playing a big role in helping Europe achieve such key policy initiatives as the EU Green Deal and Digital Transformation.  

The additional resiliency provided by Galileo enables a range of new applications and services that benefit from increased positioning reliability and further drive economic growth in Europe and beyond.

More can be found in the EUSPA EO and GNSS market report here.