GPSsüsteemidest

The GPSsüsteem (Global Positioning System) is a satellite‑based navigation system that provides global geolocation and time‑keeping services. It was originally developed by the United States Department of Defense for military navigation, but civilian access was made available in the 1980s and commercial use has since expanded worldwide. The system consists of three main segments: a constellation of at least 24 medium‑altitude satellites, the control segment on Earth that monitors satellite health and orbits, and the user segment that includes receivers ranging from handheld devices to integrated vehicle systems.

GPS receivers determine a position by calculating the time it takes for signals from at least four satellites to reach the receiver. The precise timing information supplied by atomic clocks onboard the satellites allows parallax measurements that give latitude, longitude and altitude. The system achieves typical horizontal accuracies of 5–10 meters for civilian receivers, with better performance in “Wide Area Augmentation System” or “Precise Point Positioning” modes.

Applications of GPSsüsteem on Earth's surface are extensive: navigation for maritime, aviation and automotive traffic; surveying and mapping; timing synchronization for telecommunications networks; precision farming; mobile telephony; and scientific research such as tectonic plate monitoring. However, GPS reception can be impaired by atmospheric delays, signal multipath, and intentional interference. To mitigate such issues, complementary satellite navigation systems (GLONASS, Galileo, BeiDou) are increasingly supported, and augmentation services provide enhanced accuracy and reliability.