An Introduction to Global Navigation Satellite Systems
Satellite positioning technology has come a long way since the first Global Navigation Satellite System (GNSS), the US-owned Global Positioning System (GPS) was launched in 1978. GPS provides global positioning and timing coverage that enables anyone with a GPS-enabled device to determine their precise location and time anywhere in the world.
More recently, the European Union (EU) developed its own constellation of satellites called Galileo, a competing GNSS system to GPS. Galileo, the first alternative system to GPS, was launched in 2011 and declared operational in 2020.
In this blog post, we'll compare GPS and Galileo in terms of accuracy, coverage, and other features to help you determine which GNSS system is right for you.
Accuracy
Both GPS and Galileo have similar levels of accuracy wherever in the world they operate. They use multiple satellites to calculate the user's location, which allows the system to correct for errors due to atmospheric distortion and the position of the satellites, among other factors.
However, there are small differences between the two systems, and according to the European Space Agency (ESA), Galileo has an average positioning accuracy of less than one meter, while GPS claims a positional accuracy of around 3.5 meters.
Coverage
GPS has global coverage, with its constellation of 31 satellites regularly broadcasting their signals to anyone with a GPS-enabled device. In contrast, Galileo currently has 22 satellites in orbit, with plans to increase this number to 30 by 2023. Although Galileo currently has more limited coverage than GPS, it has been designed to work in tandem with GPS and can provide additional positioning information where GPS signals may be weak.
Features
Galileo is the world's first dual-frequency GNSS system. It allows users to access signals on two frequencies, E1 and E5, which improves accuracy and provides better protection against signal interference. GPS, on the other hand, provides signals at L1 and L5 frequencies.
Another feature that differentiates Galileo from GPS is its search and rescue service known as the Galileo Search and Rescue (SAR) system. The SAR service provides accurate and rapid detection, location, and notification of distress calls from emergency beacons in case of emergencies.
Conclusion
While both GPS and Galileo offer highly accurate positioning and timing information, Galileo has a slight edge in accuracy and an advantage in offering dual-frequency signals and a search and rescue system. However, GPS still has a wider coverage range than Galileo, making it a more reliable choice in remote areas.
Ultimately, the choice between GPS and Galileo will depend on your specific needs and requirements, but it's good to know that both systems have been designed to provide highly reliable and accurate GNSS services globally.