The global positioning system, or GPS, is a type of GNSS or global navigation satellite system that the US government developed back during the late 70s. While its first use was primarily for military purposes, during the 80s the system was made available for civilian applications. This constellation of currently 31 satellites covers the Earth's complete orbit twice in 24 hours. However, alongside GPS there are other types of GNSS constellations made by different countries such as GLONASS (Russia), Galileo (EU), BeiDou (China), QZSS (Japan) and NavIC (India). A tracker for car that relies on different types of these systems is known as a multi constellation receiver and is more precise than one that relies on just one.