频谱泄漏校正的多频实信号频率估计算法

Frequency estimation algorithm for multi-frequency real signals based on spectrum leakage correction

为抑制多频实信号中负频率频谱泄漏和正频率频谱间相互泄漏对频率估计的影响,提出一种频谱泄漏校正的频率估计算法。利用FFT法对采样信号进行预处理,得到每个分量的频谱索引;对信号频谱进行插值分析,构造所有负频率和非待估计正频率的频谱插值;采用相减策略将信号频谱插值和构造的频谱插值相减,得到抑制了频谱泄漏的待估计正频率频谱插值;对生成的频谱插值进行分析,得到各分量频谱偏移量估计值;经迭代计算得到各分量精确的频率、幅值和初相位估计值。在不同频率间隔、不同信噪比等条件下的仿真实验结果表明:所提算法具有良好的频率估计性能,有效抑制了频谱泄漏的影响,提高了多频实信号的频率估计精度,使得频率估计值的均方误差更接近于克拉美罗下限。此外,在LFMCW雷达实验平台上进行了测距实验,检验了所提算法的实际应用效果。

Here,in order to suppress effects of negative frequency spectrum leakage and mutual leakage among positive frequency spectra in multi-frequency real signals on frequency estimation,a frequency estimation algorithm based on spectrum leakage correction was proposed.Firstly,FFT method was used to preprocess a sampled signal,and obtain the spectrum index of various components,and then the signal spectrum was interpolated and analyzed to construct spectrum interpolations of all negative frequencies and positive frequencies not to be estimated.Secondly,constructed spectrum interpolations were subtracted from signal spectrum interpolations using the subtraction strategy to obtain spectrum interpolations without spectrum leakage for positive frequencies to be estimated,and then the spectrum offset estimation value of each component was obtained by analyzing generated spectrum interpolations.Finally,accurate estimated values of frequency,amplitude and initial phase of each component were obtained with iterative calculation.The simulation results under different frequency intervals and different SNRs showed that the proposed algorithm has good frequency estimation performance,it can effectively suppress effects of spectrum leakage,improve frequency estimation accuracy of multi-frequency real signals,and make the mean square error of frequency estimation value closer to Cramer-Rao low Bound;ranging tests are conducted on LFMCW radar test platform to verify the practical application effect of the proposed algorithm.