基于FPGA的P码快速捕获模块设计

Design of P-code fast acquisition based on FPGA technology

摘要:

P码信号主要用于精确定位服务，比C/A码具有更强的抗干扰和保密能力，而复杂环境下弱信号捕获对灵敏度和时间指标提出了更高要求。从研究信号直接捕获算法角度出发，针对弱信号深入研究了基于快速傅里叶变换的频域伪码相位并行搜索的P码直接捕获算法的改进算法——重叠平均法，通过Matlab仿真实验，验证了算法的有效性，同时在现场可编程逻辑阵列中通过新设计思路，实现了该算法的捕获功能，且提高了硬件效率，减少了捕获时间。

Abstract:

P-code is chiefly applied to precise positioning service presently，which has a higher tolerance to jamming and spoofing compared to C/A code. Meanwhile，the acquisition of the weak signal in complicated environment requires higher sensitivity and shorter time. This paper proposes the improvement method of Fast Fourier Transform(FFT)-based acquisition searching in both frequency domain and PRN code phase domain—overlap average method. The algorithm has been validated by Matlab simulation and implemented in Field Programmable Gate Array(FPGA) by certain design. It can improve the hardware efficiency and decrease the acquisition time.