Galileo (ESA)
Galileo is the European Union's satellite navigation system, developed and managed by the European Space Agency (ESA). Named after the renowned Italian astronomer Galileo Galilei, it aims to provide accurate positioning services that are interoperable with existing systems like the U.S. Global Positioning System (GPS) and Russia's GLONASS, while maintaining full independence. The system began launching satellites in 2011, and as of 2021, twenty-eight satellites have been deployed, with plans for a total of thirty to ensure global coverage.
Galileo is designed primarily for civilian use, offering features such as dual-frequency signals for high precision, enabling location accuracy within one meter. One of its unique attributes is the ability to notify users when satellites go offline, enhancing decision-making in critical situations. Additionally, Galileo provides a search-and-rescue service that quickly relays distress signals and confirms receipt to those in need. With a focus on safety and accessibility, Galileo is positioned to support various applications, from everyday navigation to critical safety operations in transportation and rescue services.
Galileo (ESA)
FIELDS OF STUDY: Astronomy; Space Technology
ABSTRACT: Galileo is a satellite navigation system developed by the European Union (EU) and the European Space Agency (ESA). It became operational in 2016. Using data from space-based satellites orbiting Earth, Galileo can pinpoint the location of satellite-enabled devices to within a meter of their location. Galileo is designed to give the EU access to satellite navigation data that is independent of systems controlled by countries, such as GPS (the United States) and GLONASS (Russia).
Satellite Navigation Systems
A satellite navigation system uses a series of space-bound satellites traveling precise orbits around Earth to pinpoint the latitude and longitude of Earth-bound receivers with a great deal of accuracy. Satellites are highly sophisticated machines with exposure to large areas of Earth at once. This allows them to collect large amounts of data very quickly. Because satellites orbit high above Earth, beyond the planet’s atmosphere , their radio signals are not blocked by objects in the atmosphere or on the surface.
The United States and the Soviet Union developed the first satellite navigation systems. The United States began establishing its system, the Navigation Signal Timing and Ranging Global Positioning System (NAVSTAR GPS)—now usually just called Global Positioning System (GPS)—in 1978. By 1993, GPS had twenty-four satellites in orbit, giving the system worldwide coverage. Eventually, the system grew to include a total of around thirty satellites, with at least twenty-four in operation at any one time. GPS is operated and maintained by the US Department of Defense, with a subsystem made available for commercial purposes and use.
The Soviet Union (now Russia) began developing its system, the Global Navigation Satellite System (GLONASS), in 1976. Despite setbacks caused by the breakup of the Soviet Union, GLONASS was briefly operational in the mid-1990s, with twenty-four satellites in orbit. However, the system soon fell into disrepair. It was brought back online in October 2011, with twenty-four satellites again giving the system global coverage. GLONASS is operated and maintained by the Russian Federal Space Agency.
Galileo, named for famed Italian astronomer Galileo Galilei (1564−1642), is the satellite navigation system of the European Union (EU). Galileo is meant to be interoperable with both GPS and GLONASS while also being completely independent of both systems.
The European Space Agency (ESA) manages the technological development of Galileo in close cooperation with EU ministers and civil aviation experts. Galileo’s first two satellites were launched into orbit in 2011. By 2021, the ESA had launched twenty-eight Galileo satellites. The system will eventually include a total of thirty satellites that will provide worldwide coverage.
Why Navigation Systems Were Developed
Satellite navigation systems were originally conceived and designed by governments for military uses. They can be used to assist in the accurate firing of weapons, the deployment of supplies and troops, and other military operations. These systems are invaluable for search-and-rescue maneuvers, especially in terrain that is difficult to otherwise reach or view. Satellite navigation is also used to propel and guide unmanned military vehicles. The Russian and US governments can limit or reserve the strength and precision of signals from their navigational systems at their discretion.
As navigation systems grew and became more sophisticated, commercial applications became more popular. Civilian scientists used handheld units in the 1980s to provide precise locations for archaeological and geological sites. By the early 2000s, portable units were available to motorists, who used them for travel directions from one location to another. Within a few years, satellite navigation technology was being built into everything from automobiles and airplanes to farming equipment and cell phones.
Since that time, satellite navigation has been incorporated into ships, trains, planes, cars, shipping containers, and smartphones. In most cases, users do not need to know anything about where the satellites are or how they or the receivers work. They merely need to turn on their device to benefit from the automated navigation system.
While some applications of satellite navigation systems are more of a convenience, others save lives. The ability to pinpoint addresses to specific coordinates enables first responders such as firefighters, police officers, ambulance drivers, and rescue workers to more precisely identify the location where help is needed. As a result, first responders reach sites more quickly, with fewer delays caused by misdirection.
How Satellite Navigation Systems Work
Roughly twice a day, the satellites circle Earth in their unique but overlapping orbits at varying distances from Earth. Galileo’s satellites are located in circular medium-Earth orbit (MEO) about 23,222 kilometers (14,429 miles) above Earth. The satellites send radio signals to receivers based on Earth. Each satellite system is carefully calibrated so that its satellites send their signals at exactly the same time. Earth-bound receivers then calculate latitude, longitude, altitude, and time based on the amount of time it takes the signal to travel from the satellite to the receiver. Satellites are programmed and synchronized with precision so that they can locate and track an enabled receiver, such as a dedicated unit or smartphone, to within a few meters of its actual location, depending on the device’s sophistication level.
Galileo’s Rollout
The Galileo rollout was originally divided into two distinct phases: In-Orbit Validation (IOV) and Full Operational Capability (FOC). The IOV phase, which began in 2011, was designed to validate the system, to make sure that it worked as expected and successfully transmitted accurate information. IOV involved assessing performance through a variety of tests using four satellites and ground infrastructure. Galileo was validated through this phase.
The FOC phase began in 2014. Galileo began its initial operations in December 2016. Additional satellites were launched into orbit during the next few years, increasing the system’s capabilities. In December 2021, the ESA launched the twenty-seventh and twenty-eighth of an expected thirty Galileo satellites. During the FOC phase, supporting ground infrastructure was built as necessary. Eventually this will include control centers throughout Europe and a network of sensor stations and uplink stations installed around the globe. Interested parties can utilize the signals from Galileo in their products and services.
Galileo works in conjunction with the European Geostationary Navigation Overlay Service (EGNOS). This system improves the accuracy and reliability of Galileo using signals from mostly ground-based stations.
Galileo’s Services
Galileo differs from previous navigational systems in that it is designed specifically for civilian rather than military use. Unlike other countries’ systems, Galileo’s full signal strength is available for civilian and commercial purposes at all times, except in extreme circumstances such as armed conflict.
Galileo uses dual frequencies in order to deliver real-time data without delay. This allows Galileo to transmit a location to within one meter. Additionally, Galileo can inform users immediately if a satellite goes offline, helping users make more informed decisions. This feature also allows Galileo to be used for safety-critical applications, such as train automation and aircraft landing.
In addition to its free and open public service, Galileo provides encrypted, secure service mainly for government operations, and encrypted and highly accurate commercial services are available for a fee. A search-and-rescue service is used to help locate people, vessels, and aircraft in distress. This service transfers distress signals from user transmitters to regional rescue centers. An important advance in this part of the system is that it will let the user know that the signal was received and help is on the way.
PRINCIPAL TERMS
- Global Positioning System (GPS): a satellite navigation system developed in the United States; uses satellite data to determine the position, navigation, and timing of objects on Earth.
- satellite: an object that orbits another object; most commonly refers to a machine that is launched into space to orbit Earth.
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