20 18 knight navigation restores factory settings. What if there is nothing left?

20 18 knight navigation has been restored to the factory settings, and there is nothing left. You need to download the updated map package and download it again. After the car navigation is restored to factory settings, user settings and user-loaded content will be lost. At this time, you need to download the updated map package again.

Principle of automobile navigation and positioning

Because the position of satellite is accurately known, we can get the distance from satellite to receiver in GPS observation. According to the distance formula in three-dimensional coordinates, three equations can be formed by using three satellites, and the positions of observation points X, Y, Z, Y and Z can be solved.

In fact, receivers can often lock on more than four satellites. At this time, the receiver can be divided into several groups with four satellites in each group according to the constellation distribution of satellites, and then the group with the smallest error can be selected by algorithm to locate, which improves the accuracy. Due to the error of satellite orbit and satellite clock, the influence of atmospheric troposphere and ionosphere on signals, and the artificial SA protection strategy.

The positioning accuracy of civil GPS is only 100 meter. In order to improve the positioning accuracy, the differential GPSDGPS technology is widely used to establish a reference station differential substation for GPS observation, and the known precise coordinates of the reference station are compared with the observed values to obtain a correction number, which is announced to the public.