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