摘要
针对传统方法对高动态大多普勒信号捕获存在的困难,本文提出的基于FFT的捕获方法,充分考虑了高动态性的影响,改进了接收信号模型,引入了多普勒频率变化率。算法将传统的二维搜索化为了先捕获多普勒频偏及频率变化率,再捕获伪码延时的二步搜索。频偏估计方面分析了匹配傅里叶变换法和延时自相关FFT估计法,码相位估计方面分析了伪码循环相关捕获法,并对两个阶段各个方案的复杂度、抗噪声性能进行了分析和改进,降低了算法复杂度、提高了抗噪声性能,最后用MATLAB仿真验证了方法的正确性和有效性。
Traditional PN code acquisition algorithm is effectless for high dynamic Doppler shift signals.This paper presents acquisition methods based on FFT .It considers Doppler frequency change rate in high dynamic environment and improves the model of the received signal.It divides traditional two-dimensional search algorithm into the separate estimation of Doppler frequency offset and frequency change rate as well as pseudo-code phase.The complexity and signal-to-noise ratio of Doppler frequency shift estimation method,Matching Fourier Transform and Delay Self-correlation,and code phase circular correlation estimation method are analysed and improved.The simulation by using MATLAB verifies that the algorithm is correct and effective.
出处
《电子测量技术》
2015年第9期116-120,共5页
Electronic Measurement Technology
关键词
FFT
高动态
多普勒频偏
伪码捕获
FFT
high dynamic
Doppler frequency shift
PN code acquisition
