Study On Time Synchronization And Time Service With "Changhe 2" Navigation System

A Study on time synchronization and startup quick with "Changhe 2" navigation system was carried out in this paper. Feasibility of adding function of time service to "Changhe 2" navigation system was discussed.GPS invented by U.S.A in the eighties of 21st century has many virtues. But US government didn't make any promises for GPS users. It is necessary that we have our own navigation and time service system for Chinese users as an independent country. Russia has established GLONASS, and Europe countries have built their Galileo navigation system too. Now Chinese are studying our own second-generation navigation system. For construction of Chinese navigation and time service system with existing instruments we combine "Changhe 2" navigation system with BPL time service system to make "Changhe 2" navigation instruments have capabilities of both navigation and time service."Changhe 2" navigation system was established in the eighties of 21st century in our country. At the present time "Changhe 2" system can only be used for navigation purpose and cann't itself provide time service. In order to effectively exert its potential for time service, we planed to set up time synchronization of each chain in "Changhe 2" with "BeiDou 1" or GPS or BPL signals. In this way, we can establish standard time system at each station of each chain in "Changhe 2" by time synchronization between "Changhe 2" navigation system with a standard time system.In order to perform both navigation and time service of "Changhe 2" navigation system by combining it with BPL system, it is necessary that we have to establish precise time synchronization and frequency calibration between "Changhe 2" and BPL systems. The time and frequency sub-systems and GRI producer in timing units have also to be updated. A practical design has been conducted. Test results were shown and analyzed. The results demonstrated that the scheme presented in this paperis feasible and reasonable.