GPS system consists of three components- the components in the universe, control components and custom components.

Component in the universe

Component in the universe consists of GPS satellites orbiting the Earth. The number and arrangement of satellites has changed over time, and improved technical performance, as the GPS system is developed. Satellites from the BLOCK I are in operation from 1978. until 1985. and until now they are all out of function.

The original concept of Block II satellites are 24 GPS satellites that move in 6 orbital planes, equally spaced in relation to the Earth, which are tilted at an angle of 55 ° to the equatorial plane. Orbital plane is not rotated in reference to the stars. Each Space planes has a range of 4 satellites, the orbits are nearly circular (eccentricity ellipse 1 °), each properly arranged by the circle orbit, at an angle of 90 degrees. Diameter orbit is about four times larger than the diameter of the Earth and each one of the satellite orbit their range for 12 hours, so that in relation to the surface of the Earth, each satellite circle the same path every day. This number and the proper arrangement of the satellites ensure that each point on Earth is covered by at least four satellites at any time. The four satellites are needed to determine the position of a GPS receiver.

Since the satellites come out from function or for maintenance, failure or expiration of working life, the Earth orbit more satellites and currently 24 of them are active.

Control component

The control component consists of tracking satellite stations and land's antennas. Satellite tracking stations are located in Hawaii, the island of Diego Garcia, and Colorado Springs in Colorado. The role of these stations is to monitor the movement of satellite data and to send them to the main control station in Colorado Springs. These calculations are performed over land and antennas located on the other places and then the information about their exact position and time are sent to satellites. Updating is done twice a day, which made a fine setting of the system. Newer generation of satellites is able to communicate and synchronize data and the accuracy of determining the position would not be significantly impaired even when the satellites worked independently of the control components of the Earth for days.

User components

User components are the GPS receivers on the Earth. Receivers can be components included in other devices such as mobile phone, clock, and the like, or stand-alone devices. For example, a GPS receiver based on SiRF Star III chip has dimensions of only 12 x 15 mm. Second, individual devices have a display for displaying the position, velocity and / or time and may have interfaces with other devices.

Basic components of GSP receiver are antennas those are set to the frequency of the GPS satellites, crystal oscillator, which serves as a clock and a microprocessor that processes signals. Receivers are often described by how many channels they have. Each channel is followed by a satellite. Older models had four to five channels, and today mostly 12 to 20 channels.