In our daily life, we have to use the map navigation software on our mobile phones. In order to realize navigation, positioning is needed first. Only when the positioning is accurate can the navigation planning route be meaningful. So do you know what these map navigation software rely on to locate us? Let's learn about the global positioning system GPS.
Global Positioning System (GPS) is a global satellite navigation and positioning system developed by the US government and military. Completed and put into use on 1994. GPS system consists of three parts: space part, ground part and user part.
The system includes 3 1 space GPS satellite; There are 1 master control station, 3 data injection stations and 5 monitoring stations on the ground, as well as GPS military receivers and smart phones as users. At least four satellites are needed to quickly determine the position and height of the client on the earth; The more satellite signals can be received, the more accurate the decoded position will be.
What is GPS?
GPS is the abbreviation of global positioning system, that is, global positioning system. It is a high-precision radio navigation and positioning system based on artificial earth satellite, which can provide accurate geographical position, vehicle speed and accurate time information anywhere in the world and near-earth space. The service life of GPS working satellites is about seven and a half years, so new satellites need to be launched every year.
How is GPS located?
Satellites in earth orbit will broadcast signals, which mainly send out three kinds of information: the time of sending signals; The position of my satellite; The height of my satellite. These signals are sent to the outside world through standard protocols, and terminals equipped with GPS chips can receive and interpret these signals.
Theoretically, a terminal needs to receive four satellite signals, so the position can be calculated by a calculation formula. The more satellite signals it receives, the more accurate its position will be. But the result calculated in this way is biased, because the satellite is moving at high speed, compared with us, there is a speed difference. According to the principle of relativity, clocks are inconsistent. Therefore, based on the principle of relativity, the terminal can get its own position after correction.
What other satellite positioning systems are there?
At present, there are four global satellite navigation systems in the world, including the global positioning system (GPS) in the United States, GLONASS in Russia, Galileo in Europe and Beidou in China. These four satellite navigation systems are the four core suppliers of global satellite navigation systems identified by the United Nations Satellite Navigation Committee.