Research And Implementation For Receiving Algorithm Of New Generation Satellite Signal Based On Fpga

Satellite navigation system has entered the period of rapid development and become the third growth point of electronic information industry. MBOC(6,1,1/11) signal will be adopted in modern satellite navigation systems. Compared to acquisition for conventional pseudo code, acquiring this new signal is much more difficult, especially in the hardware implementation. Taking the Galileo MBOC signal as an example, this paper designs acquisition algorithm, which is implemented on FPGA. The main contributions of the paper are:1) Based on FPGA development technology, design pseudo code generator, sub-carrier and IF carrier generator, and realize IF Galileo MBOC signal simulator. As the receiver end, AD converter, DPRAM and serial port are controlled by FPGA to collect signal.2) The acquisition principle of MBOC signal is analysised in this paper. Through comparing between serial search acquisition and parallel acquisition, it can be concluded that the calculation amount of parallel acquisition is much less. Achieve the parallel acquisition based on FFT and acquire the Galileo signal successfully by Matlab.3) The FFT in parallel acquisition algorithm takes a large number of operations and the hardware cost is rather high, which caused by the Wide bandwidth of MBOC signal and long pseudo code cycle. To solve this problem, this paper uses the average-correlation method for reference to design Average-Correlation acquisition algorithm based on FFT and test the performance of this algorithm by Matlab simulation.4) The modules of Average-Correlation acquisition algorithm based on FFT, including demodulation, average-correlation, FFT/IFFT, complex multiplication, modulus square, threshold decision and so on, are designed in verilog hardware description language and optimized preliminary. Verify the feasibility and correctness of this system though simulate on Modelsim and downloading test on ALTERA EP2S180F1020C3 FPGA chip.