基于功率谱形态学运算的LFM信号参数估计

Parameters estimation of LFM signals based on morphology operations

针对当前线性调频(linear frequency modulation,LFM)信号参数估计算法中存在的估计精度与计算量的矛盾问题,提出了一种基于功率谱形态学运算的信号参数估计算法。该算法根据LFM信号参数与功率谱形状特征的关系,实现了LFM信号参数估计。仿真试验表明,在信噪比为-5dB时,LFM信号的调频斜率和起始频率估计精度分别比基于Radon模糊变换(Radon-ambiguity transform,RAT)和分数阶傅里叶变换(fractional Fourier transform,FRFT)结合的离散谱校正算法提高了约2%和4.5%,带宽和脉冲宽度估计的均方根误差分别小于2.4MHz和0.025μs;当采样点不大于4 096时,计算量比插值FRFT算法降低了约70%,证明了该算法具有高估计精度和低运算量的优点。

A parameters estimation method based on morphology operations is proposed to estimate the parameters of linear frequency modulation （LFM） signals, to resolve the contradiction between the estimation accuracy and the computation. According to the relationship between the parameters and the shape features of signal power spectra, the parameters of the LFM signals can be calculated. The experimental results demonstrate that the estimation accuracy of the chip rate and initial frequency can increase by about 2 % and 4.5 %, compared with the discrete spectrum correction method based on Radon-ambiguity transform （RAT） and fractional Fourier transform （FRFT） when signal to noise ratio （SNR） is -5 dB, respectively. The root mean square errors （RMSE） of band width and pulse width estimation are less than 2.4 MHz and 0. 025 μs, respectively. At the same time, the method can reduce the computational complexity by about 70% with the interpolation algorithms based on fractional Fourier transform （FRFT） when N≤4 096. And the simulation results prove the method has the advantage of high estimation accuracy and less computation.