基于分数阶傅里叶变换(Fractional Fourier Transform,FRFT)对线性调频(Linear Frequency Modulated,LFM)信号参数进行估计,问题关键是确定FRFT最佳阶数,根据误差迭代思想提出新的参数估计算法,该算法利用归一化带宽和旋转角的转化关系,由估计误差推算角度差值,有效降低了运算量,不需要调频斜率正负的先验信息,改进的对数搜索算法可以进一步提高参数估计结果的稳定性和可靠性.仿真结果表明,信噪比在-8dB以上时该方法在高效率的前提下仍具有良好的参数估计性能,平均估计误差在 1%以内,估计结果接近Cramer-Rao下限,满足工程实时处理需求.
A fast parameter estimation algorithm for LFM signal under low SNR based on FRFT
To estimate the parameters of Linear Frequency Modulated(LFM)signal based on Fractional Fourier transform(FRFT),the key issue is to determine the optimal order of FRFT.A new parameter estimation algorithm is proposed based on the idea of error iteration.The algorithm utilizes the conversion relationship between normalized bandwidth and rotation angle.Calculating the angle difference from the estimation error effectively reduces the amount of computation and does not require the prior information of positive and negative frequency modulation slope.The improved logarithmic search algorithm can further improve the stability and reliability of parameter estimation results.The simulation results show that the proposed method still has good parameter estimation performance under the premise of high efficiency when the signal-to-noise ratio is above-8 dB.The average estimation error is less than 1%,and the estimated results are close to the Cramer-Rao Lower Bound,meeting the requirements of engineering real-time processing.
Low signal-to-noise ratio(SNR)Fractional Fourier Transform(FRFT)Linear Frequency Modulation(LFM)signalparameter estimation
万方数据
维普
