COMPASS and GPS double system second difference switching method

Abstract

A dual system second time difference switch method of Northern dipper and GPS involves a phase discriminator and is characterized by also involving a time difference identification module and an intelligent control module; the phase discriminator is realized through a hardware platform FPGA and the phase difference of timing signal of the Northern dipper system and GPS is measured out; the phase difference is sent to the time difference identification module for statistical analysis and amendment; the identification difference after analysis is sent to the intelligent control module for the control in switching process. The high precision phase discriminator in the invention continuously carries out phase discrimination for local time scale and the time scale of the Northern dipper system and for local time scale and the time scale of GPS as well; the long-term statistics for value of phase difference is implemented to obtain an accurate value of phase difference, finally the time-frequency output quantity is slowly adjusted. The method well solves the integration problem between the Northern dipper system and GPS and significantly improves the integral time service performance of product.

Description

technical field [0001] The invention relates to a time difference switching method, in particular to a second time difference switching method of Beidou and GPS dual systems. technical background [0002] At present, satellite timing equipment under the GPS system is widely used in our country, but there are great potential safety hazards. The "Beidou-1" satellite navigation and positioning system is an all-weather, regional satellite navigation and positioning system independently developed by China. The three major functions of Beidou and GPS have appeared in the market, and there is a problem of switching between Beidou and GPS time scales in these products. The time scale signal of the Beidou system and the time scale signal of the GPS system At the same time, it is used as the tracking reference source of the local system, but the time scale signals of the Beidou system and the GPS system have systematic differences, and the delay error introduced by the unhealthy ephem...

AI Technical Summary

Problems solved by technology

[0002] At present, satellite timing equipment under the GPS system is widely used in our country, but there are great potential safety hazards. The "Beidou-1" satellite navigation and positioning system is an all-weather, regional satellite navigation and positioning system independently developed by China. The three major functions of Beidou and GPS have appeared in the market, and there is a problem of switching between Beidou and GPS time scales in these products. The time scale signal of the Beidou system and the time scale signal of the GPS system At the same time, it is used as the tracking reference source of the local system, but the time scale signals of the Beidou system and the GPS system have systematic differences, and the delay error introduced by the unhealthy ephemeris, the transmission attenuation of the wireless link, the multipath effect, and the external interference Both bit error and delay jitter will cause the drift of the satellite time scale signal. If the time scale phase difference between the Beidou and GPS systems cannot be accurately identified, or the switching strategy is improper, it will cause the local time scale signal to jitter, directly affecting the time service. The timing performance of the system has deteriorated. At present, there is a common defect in the switching strategy of this type of product. The time scale switching process of the dual system is too simple, there is no continuous statistics on the phase difference of the time scale signal of the dual system, and the switching process is also lacking. Considering the complex situation, even switching directly without considering the phase difference, resulting in reduced timing performance, the second signal switching method in this paper solves this problem very well

Images