System parameters of global satellite navigation and positioning system

The United States Global Positioning System (GPS) has been developed since 1970s, and consists of 2 1+3 polar-orbiting satellites, which are divided into 6 orbits. The inclination of the track plane is more than 60 degrees, and the track is about 20 thousand kilometers from the ground. The orbit of the satellite around the earth is slightly less than 12 hour. The satellite continuously sends two navigation signals encoded by pseudo-random noise to the whole world, one of which is called C/A code, which is a civil coarse code. One is called code P, which is used by the special forces designated by the system. Navigation signals include satellite operation parameters and clock correction data. For the receiving user terminal to calculate and locate by itself. The GPS system has been put into operation, and its positioning error is generally less than100 m. Using differential GPS positioning method can greatly improve the positioning accuracy.

GLONASS is a global navigation satellite system of the former Soviet Union, similar to GPS. It was launched in the 1970s and began to launch experimental satellites in the early 1980s. It is expected that it will be fully put into use in the late 1990s. In full operation, the number of constellation satellites is designed to be 2 1+3, the inclination angles of the three orbits are more than 60 degrees, and the height of the orbits from the ground is about 1.9 million kilometers.