Abstract: Based on the average correlation acquisition algorithm and the progressive code phase acquisition algorithm, this paper optimizes the coarse/fine acquisition method, and proposes the average asymptotic method for fine acquisition. The improved algorithm only uses a single sequence to search for the carrier frequency during coarse acquisition, and performs fine acquisition after successful coarse acquisition. When acquiring finely, the sequence is selected according to the average asymptotic method and then processed, which not only ensures the accuracy of the code phase, but also reduces the amount of computation. When the receiver sampling frequency is 16.368 MHz, the improved acquisition algorithm achieves a 43.53% reduction in computation compared to the existing acquisition algorithm. Based on the improved acquisition algorithm, a frequency domain acquirer with parallel unfolding structure is designed, and its hardware implementation is completed on the Xilinx Virtex-7 field programmable gate array (FPGA). The result shows that the acquisition time of the frequency domain acquirer for a single satellite is less than or equal to 2.88 ms, enabling fast and effective signal acquisition.
Keywords: average correlation; fast acquisition; carrier frequency; global positioning system(GPS); field programmable gate array(FPGA)
合肥工业大学学报自科版