Journal of Shanghai Jiaotong University ›› 2012, Vol. 46 ›› Issue (11): 1843-1847.

• Radiao Electronics, Telecommunication Technology • Previous Articles     Next Articles

A Delay Measurement Algorithm of C/A Signal Transmission Channel for GPS Satellite

 CUI  Xiao-Zhun, MI  Hong, LI  Yi, CHEN  Zhong-Gui   

  1. (Institute of Spacecraft System Engineering, China Academy of Space Technology,  Beijing 100094, China)
  • Received:2012-03-02 Online:2012-11-30 Published:2012-11-30

Abstract: The delay measurement accuracy of the transmission channel directly affects GPS users’ positioning precision and time transfer accuracy of GPS. To measure delay of C/A (Coarse/Acquisition)signal transmission channel high accurately, a delay measurement algorithm based on DSP (Digital Signal Processing) was introduced. The C/A signal and the pulse of Z counter of time keeping system on GPS satellite are sampling in synchronization. After C/A signal data pre-processed, multi-rate digital processing is made to decide the start point of PRN (Pseudorandom noise) code of C/A signal. With the processing results of Z pulse signal data, the delay of C/A signal channel is calculated out. The measurement uncertainty with the proposed algorithm is less than 0.2 ns when the sampling frequency is 10 Gsa/s.  

Key words: global positioning system (GPS), satellite, coarse/acquisition signal, transmission channel, delay measurement

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