Research On High-Speed High-Sensitivity Acquisition And Tracking Algorithm Of Satellite Navigation Signal And ASIC Design Of Satellite Time Service Chip

With the rapid development of satellite navigation systems in recent years, the navigation receivers have gained wide applications. As the core technology of navigation receivers, acquisition and tracking algorithm has become a research hotspot. This paper proposes a high-speed high-sensitivity acquisition and tracking algorithm for GPS, which can be easily modified to be used for BDS-Ⅱ developed by China; based on the proposed algorithm, this paper designs a low-cost low-power satellite time service chip with20-millisecond accuracy for civilan applications.Firstly, this paper analyses the structural features of GPS signal and acquisition and tracking principles. The performances of several traditional acquisition and tracking algorithms are compared; and then, this paper proposes a high-speed high-sensitivity acquisition and tracking algorithm. By introducing a SRAM to store data, the proposed algorithm gets the satellite number, carrier frequency and C/A code phase through the1-millisecond acquisition. On this basis, it performs the8-millisecond acquisition and tracking for one single visible satellite to demodulate ephemeris to gain time parameters. Besides, this paper designs an independent GPS development platform to optimize the required design parameters and verify the feasibility of the design. Finally, the satellite time service chip is implemented and ready to tapeout with SMIC0.18um CMOS process. The ASIC design works include logic synthesis based on DFTC, static timing analysis(STA), formal verification, automatic test pattern generation(ATPG), place and route, parasitic parameter extraction(RCX) and physical verification(DRC and LVS).FPGA verification results show that the high-speed high-sensitivity acquisition and tracking algorithm proposed in this paper has a very strong practicability. In strong signal environment, the acquisition and tracking for GPS siganal can be implemented within two seconds, while the ephemeris demodulation can be completed in no more than twenty seconds. In relatively weak signal condition, such as between buildings, on city streets and so on, the precise GPS satellite time service can also be realized correctly. In addition, ASIC design results show that the GPS satellite time service chip designed in this paper has a broad application prospect in the civil market with the advantages of small-size, low-power and low-cost.