Currently on the market of telematics services are a lot of GPS-navigation systems, each of which has its own personality: the application, additional functionality, technical parameters, as well as prices and payment methods. Nevertheless, based on all existing systems are "two China", a mobile communication and satellite navigation (GPS). In the last decade, both of these areas have undergone rapid development. As a result, mainstream consumers have become available reliable and inexpensive mobile terminals and satellite navigation (GPS), complex and cumbersome predecessors have previously been supplied solely for the department of defense agencies and special services. One of the major advantages of gps Navigators to pre-existing ground-based systems is the reliability and independence of weather conditions. Regardless of what you are using a gps Navigation – gps program is ready to show your location at a time when you need it. gps system comprise 24 satellites, ground stations and tracking combined into one common network.

Satellites revolve around the Earth at an altitude of 20 thousand kilometers in six circular orbits, which are located at an angle of 60? to each other. The period of revolution of each satellite is 12 hours. Installed on satellites atomic clocks, which provide perfect precision timing. Satellite transmitters operate at a frequency of 1575.42 MHz. Signal is received gps receivers, which are adopted from satellite data using a special algorithm calculates the position. gps receiver periodically receives from the satellite packets of information containing the information about themselves satellites, the current date and time, as well as the exact time of sending each packet of information. Based on the data receiver determines the distance to each satellite, their relative position and calculates its coordinates in a mathematical formula. The distance to the satellites is determined by the delay time the message was received with respect to the gps receiver time of sending messages from the satellite. In addition to the coordinates on the terrain, the receiver is able to determine altitude and speed of the object.