Galileo: An introduction to Europe’s global, satellite-based navigation system

Satellite positioning and digital navigation have been seamlessly integrated into our daily lives. And while some may think we can get by with old-fashioned paper maps, the truth is that most of us are highly dependent on digital maps to get us from point A to point B. Galileo, Europe's own Global Navigation Satellite System (GNSS), provides accurate and up-to-date navigation information to nearly four billion devices worldwide.

But in addition to helping you commute to work or avoid getting lost while backpacking, Galileo supports the daily operations of a wide range of industries such as transport, logistics, telecommunications, and energy. 

In this Observer, we'll delve into the complexities of Galileo, uncovering its components, the steps taken to get it up and running, and the impactful ways in which it has improved the lives of millions of people in Europe and around the world.

What is Galileo?

Galileo is not just a system of satellites—it is Europe's response to evolving global navigation demands and the critical need to avoid dependence on another continent for services that are critical to infrastructure and daily life. Providing highly accurate positioning, navigation, and timing services, free of charge and under civilian control, Galileo is one of the four existing Global Navigation Satellite Systems, the other three being the US GPS, the Russian GLONASS, and the Chinese Beidou. 

The Galileo system consists of satellites in orbit and several ground stations strategically deployed across the globe. The Galileo satellites are positioned in three orbital planes at an altitude of 23,222 km in Medium Earth Orbit (MEO), ensuring continuous global coverage 24/7.

The ground segment consists of two main control centres, one in Fucino (Italy) and the other in Oberpfaffenhofen (Germany), which control the satellites and manage the navigation system. Additionally, the ground segment includes the European GNSS Service Centre (GSC) located in Torrejón (Spain), the Galileo Security Monitoring Centre (GSMC) with facilities in St. Germain-en-Laye (France) and Madrid (Spain), and the Galileo Reference Centre (GRC) located in Noordwijk (The Netherlands). These facilities play crucial roles in the operation and performance monitoring of the Galileo system, ensuring its accuracy and security.

A global network of 15 Galileo Sensor Stations (GSS) checks the accuracy and signal quality of each satellite in real time. Data from these stations is transmitted to the control centres which:

• Make sure satellites accurately transmit their position and time;
• Check the reliability of satellite signals and identifies any malfunctions; 
• Synchronise the time on all satellites for accurate distance and location measurements.

These elements are crucial for the Galileo system to provide reliable and precise global positioning services.

Multiple services, tailored to citizens’ needs 

The true measure of Galileo's success is its impact on the lives of millions of people around the world. Galileo allows users to determine their exact location with greater accuracy and precision than any competing system and is approximately 4 times more precise than GPS. Beyond individual convenience, Galileo is a catalyst for European innovation, creating jobs and securing a significant share of the global GNSS market. 

Galileo's range of services is further proof of its importance. The Open Service provides free global positioning, navigation, and timing/synchronisation services, already used in applications such as automotive navigation and location-based mobile phone services as well as in many professional applications in agriculture, transport, and surveying. Precise time and synchronisation are critical aspects of a wide range of strategic activities around the world. It is a crucial, but often unrecognised, part of today's modern infrastructure, especially in the case of systems that support societal functions such as health, safety, and security. GNSS timing services, essential for the precise synchronisation needed for mobile phone networks management, energy sector applications such as smart electricity grids, and banking transactions, are globally accessible. They provide users with access to global time standards, achieving accuracies within a few tens of nanoseconds.

The new High Accuracy Service goes one step further by providing even more accurate signals, delivering horizontal accuracy down to 20 cm and vertical accuracy of 40 cm. These are important for many applications from precision farming, to geodesy, and even autonomous vehicles.

An Open Service Navigation Message Authentication Service (OSNMA) will soon allow the users to check the authenticity of the GNSS information and thus reduces considerably the risk of spoofing (i.e., falsification of GNSS signals for malicious purposes).

The Public Regulated Service, which will provide position and timing only to governmental authorised users, will ensure a high level of service continuity, robustness and security for sensitive applications.

In addition to these satellite navigation services, the Search and Rescue Service contributes to the international COSPAS-SARSAT organisation which is a cooperation for search and rescue operations. As part of this service, Galileo satellites pick up signals from emergency beacons on aircraft and ships or from individual portable devices and relay precise locations to national rescue centres, informing authorities of the location of an emergency or accident. Since January 2021, an additional feature has been added to this service: the Return Link Service (RLS). With RLS, Galileo not only locates people in distress and communicates their position to the relevant authorities but also sends an automatic acknowledgement back to the user, letting them know that their request for help has been received and their position is known.

A collaborative European effort

Behind the scenes, Galileo is not just a technological marvel, but a collaborative effort. It is managed and funded by the European Commission as a flagship component of the EU Space Programme. The European Space Agency (ESA) is leading the design, development and qualification of the space and ground systems. To ensure a seamless transition from design to reality, the EU Agency for the Space Programme (EUSPA) acts as a service provider and is in charge of some facilities such as the GNSS Centre or the Galileo Security Monitoring Centre, monitoring market needs, applications, and user engagement.

What comes next?

Although Galileo has already achieved remarkable results, its story is far from over. On the horizon is the second generation of Galileo satellites—an evolution of the existing generation. Twelve more powerful satellites are being developed, equipped with fully digital payloads, electric propulsion, advanced navigation antennas, improved atomic clocks and additional robustness and security features. What's more, the satellites will be built in such a way that they can be reprogrammed while in orbit—a feature that will allow to make rapid changes in response to market demand. 

New services are also on the way, including the new Emergency Warning Satellite Service (EWSS). This service will provide direct warnings to populations confronted with the consequences of natural or human-made disasters. EWSS will enable the National Civil Protection services to transmit information related to the hazard, including its severity, time of onset, expected duration and impacted areas, as well as instructions directly through smartphones and navigation devices using the Galileo infrastructure. Expected to be operational in 2025, EWSS is designed to complement existing warning systems, particularly in remote and rural areas or where networks are congested. It has been successfully tested to provide rapid alerts within 60 seconds. Once launched, it will be available free of charge to EU civil protection authorities, strengthening disaster management alongside the Copernicus Emergency Management Service (CEMS).

Galileo reflects Europe's commitment to advancing global navigation technology. With its growing constellation of satellites and ground stations, this system not only improves the precision of location-based services but also bolsters various sectors of the EU economy. As Galileo progresses with the introduction of second-generation satellites and new capabilities, its role in shaping the future of global navigation and its impact on everyday life and industry will continue to grow.