Research And Implementation Of Timing Technology Based Beidou System

Precise time-service is the safty insurance in the military, electric power, communications, transportation and other industry security system operation.Developing the satellite system of China's independent intellectual property effects the economic development and national security. At present, the majority of industries in China use GPS navigation systems, in order to break the monopoly of GPS, for the benefit of our economic and national security, in 2003 China established "Compass I" satellite navigation systems, that is Beidou system. Beidou satellite navigation system is built independently by China and it provides a regional all-weather, high precision navigation service with three basic functions of positioning, communication, and time-service.This paper based the "Compass I" time-service receiver project of some navigation department. I had the opportunity to participate in the development of a one-way direction of Beidou system time-sevice receiver. The main contents of this paper is as follows:First, Make a brief overview of the global satellite navigation system, Specifically descripts Beidou satellite system structure, Beidou navigation data structure, the receiver hardware circuit, one-way direction timing principle, these are the fundamentals of understanding satellite signal processing techniques and timing Solution.Next, the processing of baseband signal after the antenna and the RF module, mainly introduces the digital matched filter acquisition, Costas tracking loop, and Viterbi decoding, CRC check, to get satellite navigation message. This part of the technology is the Key part not only in the timing receiver but also in a navigation receiver.Finally, Describes the Solution Process of signal sending time, the delay of signal transmission, the correction method of up-down link delay, tropospheric and ionospheric delay, ultimately to achieve the Beidou system time in an allowable error less than 100ns. I design an optimized PPS model which integrate with the sub-frame count and high-precision local oscillator counter. In the end, I proposes a Chebyshev polynomial fitting algorithm to Estimate satellite position to improve timing accuracy.Project successfully worked out the timing receiver with high precision and stability, and the error less than 100ns.