The GPS (Global Positioning System) is the only fully functional Global Navigation Satellite System that enables a GPS receiver to determine its location, speed, direction, and time with the help of precise microwave signals. It was developed by the United States Department of Defense, and was christened officially as NAVSTAR GPS. Generally GPS is widely used around the globe as a useful tool for map-making, land surveying, commerce, and scientific uses. It is also an ingredient product in the scientific study of earthquakes, and synchronization of telecommunications networks. It is through three or more than three GPS satellites, the GPS calculates position.
GPS technology is divided into three major segments; (1)- space segment (SS), (2)- control segment (CS), and (3)- user segment (US). To calculate the position by a GPS receiver, it requires the current time, the position of the satellite and the measured delay of the received signal. The position accuracy is basically dependent on the satellite position and signal delay. With the help of higher-chip-rate P(Y) signal, position accuracy can be improved. Assuming the same 1% bit time accuracy, the high frequency P(Y) signal results in accuracy of about 30 centimeters.
Atmospheric conditions can play an important role in the speed of GPS signals. Any inconsistency in the atmospheric condition can affect the speed of the GPS signals as they pass through the Earth's atmosphere and ionosphere can affect the speed of the GPS signals as they pass through the Earth's atmosphere and ionosphere.
The US decided to develop GPS during the cold war. The launching of Sputnik by the Soviet Union motivated NASA for the development of this project to trace the movements of the satellite Sputnik which later started using for civilian purposes. In the present days the purposes of GPS ranges from path finding for drivers to gathering of information on climatic conditions.
