Satelliittipaikannusjärjestelmä

Satelliittipaikannus, often referred to as satellite positioning, is a system that determines the geographical location of a receiver anywhere on or near the Earth. It relies on signals transmitted from a constellation of satellites orbiting the planet. The most well-known satellite positioning system is the Global Positioning System (GPS), operated by the United States. Other prominent systems include the Russian GLONASS, the European Galileo, and China's BeiDou.

A satellite positioning receiver, such as those found in smartphones or dedicated navigation devices, listens for signals from multiple satellites. Each signal contains information about the satellite's identity, its precise orbital position, and the exact time the signal was transmitted. By measuring the time it takes for these signals to reach the receiver, and knowing the speed of light, the receiver can calculate its distance from each satellite. Using a minimum of four satellites, the receiver can triangulate its position in three dimensions (latitude, longitude, and altitude).

The accuracy of satellite positioning can be affected by various factors, including atmospheric conditions, obstructions like tall buildings or dense foliage, and the geometry of the satellites in the sky. Despite these potential limitations, satellite positioning has become indispensable in numerous applications. These include personal navigation for vehicles and hikers, surveying and mapping, precision agriculture, fleet management, and scientific research. The technology continues to evolve, with ongoing efforts to improve accuracy, reliability, and availability.