The Research And Realization Of Beidou System Timing Service Terminal

Beidou system is the first generation satellite navigation and positioning system of China independent. As an important national information infrastructure, it plays a major role in national defense and the national economy in our country. However, Beidou satellite timing service development far less than the positioning and communications functions, many fields development which of needs high-precision time synchronization has been monopolized by GPS. With the electric systems, telecommunications and transportation systems, network structure and the operating mode complexity, requirements of the time frequency precision as getting higher and higher, for the security and reliability of time synchronization needs to increase other time synchronization systems to prepare each other. Combined with a Satellite timing service item, the author involved in the research and development of Beidou passive Satellite timing service terminal. The major work can be concluded in three aspects as follows:Firstly, detailed analysis the main factors of impair satellite timing service quality, build a packet arrival time projection model based on Beidou super-frame signal, make the time delay from the fixed value of super-frame accurate to the specific value of each sub-frame; proposed the thought of use pulse time intervals determine to elimination the leakage-pulse and the multi-pulse, and based on this idea have established stable 1pps sync pulse output model.Secondly, because the clock differential of receiver, atmospheric delay errors have significant impact on the results of the process of passive positioning, design of a location algorithm based on the passive delay differential, using the equal time of the signal sent by the control center throuth all of satellites to the receiver, differential the receiver delay, better to overcome the impact of the error, greatly improving the accuracy of positioning and timing.Finally, by using the strategy of sub-blocks to collect, updates satellite navigation information and updates the location information, speed information, the time information of uplink delay and communication time delay, to ensure that the correct information quickly update.Based on the results of these studies, the project team has developed a passive Beidou System Timing Service Terminal(BD-TS), it passives the positioning accuracy to 100 meters, and the timing service precision in about 100 ns, so that it promotes the Beidou timing service products to develop in the direction of civilian.