How many satellites does Beidou have?

1.On June 23rd, 2020, the last networked satellite of xichang satellite launch center Beidou-3 global satellite navigation system was launched. With the satellite successfully entering the scheduled orbit, all 55 satellites of Beidou satellite navigation system were launched into the network. At this point, the global networking of Beidou system has been officially successful, which indicates that Beidou ranks among the top navigation and positioning systems in the world.

2. Because the position of the satellite is accurately known, we can get the distance from the satellite to the receiver in the observation of the satellite by the receiver. Using three-dimensional coordinates and the distance formula in three satellites, three equations can be formed to solve the position (x, y, z) of the observation point.

3. Considering the error between the satellite clock and the receiver clock, there are actually four unknowns, X, Y, Z and the clock difference, so it is necessary to introduce the fourth satellite to form four equations to solve, so as to get the latitude, longitude and elevation of the observation point.