基于两级傅里叶变换迭代算法的载频估计方法

Frequency Estimation Based on Two-stage Fourier Transform Iterative Method

雷达信号处理中,载频估计尤为重要,目前基于两级M-Rife的估计算法能够实现多个脉冲联合频率估计,但是在低信噪比条件下估计精度较低且容易出现较大的估计偏差。针对该问题,在傅里叶变换迭代的基础上,提出了一种基于两级傅里叶变换迭代法的载频估计方法。该方法首先使用傅里叶变换迭代法对单个脉冲进行载频估计,其次将每个脉冲的载频估计值进行平均处理作为载频粗估计,利用得到的载频粗估值进行下变频处理并将多个相参脉冲等效为一个正弦信号,最后使用一次傅里叶变换迭代法进行载频估计。实验结果显示,该方法对脉冲串信号可以实现高精度载频估计,且估计精度优于基于双级M-Rife的估计算法,能够在更恶劣的传输环境中使用。

In radar signal processing,carrier frequency estimation is particularly important.The cur-rent estimation algorithm based on two-stage M-Rife can achieve joint frequency estimation of multi-ple pulses,but the estimation accuracy is low under the condition of low signal-to-noise ratio and large estimation deviations are prone to occur.To address this problem,based on the Fourier trans-form iteration,a carrier frequency estimation method based on the two-stage Fourier transform itera-tive method is proposed.This method first uses the Fourier transform iterative method to estimate the carrier frequency of a single pulse,and then averages the estimated value of the carrier frequency of each pulse as a rough estimate of the carrier frequency,and finally uses the obtained rough estimate of the carrier frequency for down-conversion and processing.The multiple coherent pulses are equiv-alent to a sine signal,and then the Fourier transform iteration method is used to estimate the carrier frequency.Experimental results show that this method can achieve high-precision carrier frequency estimation for burst signals,with the estimation accuracy better than the estimation algorithm based on two-stage M-Rife,and it can be used in more severe transmission environments.