Global Positioning System

Imagne we are in a place, which has no previous history about that place. We need information about our exact location on earth surface. Expression of the location information can be realized based on a geographic coordinate system (GCS). The GCS expresses location on earth in two axes, the horizontal axis (latitude) and the vertical axis (longitude). The latitude is a horizontal line that measures the angle between a certain location on the earth and the equator. The longitude is a vertical line that measures the angle between a certain location on the earth and the zero point on Earth as reference (Greenwich in London, UK).

Global Positioning System (GPS) is a satellite-based device that determines a user's location by receiving signals from satellites. GPS uses 24 satellites that send microwave signals to Earth. These signals are received by a receiver on the surface to determine position, speed, direction, and time. Navigation is a process of finding accurate loaction and planning to move following route. Navigation is concerned with finding location the way to reach targeted destionation. The GPS is a type of positioning satellite system, it is apart of Global Navigation Satelite System (GNSS). GNSS is general term of positioning and navigation system that include GPS satelite and other satelites that providing information for positioning, navigation, and timing (PNT). The GPS has been developed by the US Department of Defence (DoD), and it is widely used GNSS.