The Global Positioning System (GPS) is a network of satellites orbiting the Earth at an altitude of 20,000 km. Once it has information on how far away at least three satellites are, your GPS receiver can pinpoint your location using a process called trilateration. The orbits are designed so that there are always 6 satellites in view, from most places on the earth. GPS uses a lot of complex technology, but the concept is simple. The GPS receiver gets a signal from each GPS satellite. The satellites transmit the exact time the signals are sent. GPS systems are extremely versatile and can be found in almost any industry sector. They can be used to map forests, help farmers harvest their fields, and navigate airplanes on the ground or in the air. GPS systems are used in military applications and by emergency crews to locate people in need of assistance.
Real Time Kinematic (RTK) satellite navigation is a technique used to enhance the precision of position data derived from satellite-based positioning systems (global navigation satellite systems, GNSS) such as GPS, GLONASS, Galileo, and BeiDou.