The principle of satellite navigation is that each navigation satellite continuously transmits its time-varying precise position to the ground. After receiving this information, the satellite positioning receiver on aircraft, ships and other means of transportation will quickly calculate its own position, thus achieving the purpose of navigation.

Shortly after the successful launch of the first artificial earth satellite, at the end of 1957, two doctors in the applied physics laboratory of Hopkins University in the United States received the radio signal sent by the satellite of the former Soviet Union with a radio receiver. One of them is Gilles and the other is Weifenbach, both of whom are radio lovers. They found that the frequency of the received radio waves had a "Doppler effect" with the movement of the satellite (that is, when the wave source moved relative to the observer, the frequency received by the observer was different from the frequency emitted by the wave source). Just like the train running to the listener, the whistle will become higher in tone; When you fly away from the audience, the whistle will be lower. This reminds them that the satellite orbit can be determined by measuring the frequency shift of the ground station. They developed an algorithm to determine the entire satellite orbit according to the measured frequency shift data. Two other doctors in this laboratory, Dr. Macclure and Dr. kershner, further imagine that if the compiled program is used in reverse, the position of the ground receiving station can be calculated from the known precise orbit of the satellite, thus forming the concept of satellite navigation, that is, positioning by using the Doppler effect of the satellite and Greenwich Mean Time to realize navigation.

1958 In February, the satellite navigation research group led by Hopkins University was established and the meridian satellite navigation plan was implemented. /kloc-0 was officially delivered to the navy in July, 1964, and/kloc-0 began to enter the civil field in June, 1967.