一种分数域二分法 LFM 信号参数估计方法

针对传统基于分数阶傅里叶变换（fractional Fourier transform，FRFT）的线性调频（linear frequency modulated， LFM）信号参数估计方法中估计精度和计算量难以同时满足实际要求的问题，提出一种分数域二分法的 LFM信号参数估计方法。该方法分析量化了变换阶次误差对参数估计误差的影响，利用单分量 LFM信号变换阶次和分数域展宽的关系，通过迭代不断缩小变换阶次的取值范围，获得满足初设阈值的最优阶次，并利用最优阶次和峰值位置对 LFM信号进行参数估计。采用逐次重构消除的方法，可以对强弱混合的多分量 LFM信号进行参数估计。仿真结果表明，在满足信噪比要求的条件下，该方法能够有效地对 LFM信号进行参数估计，可以通过参数估计精度的要求选择不同阈值，与传统方法相比，在参数估计精度相当的情况下大大地减小了计算量。

Fractional domain dichotomy LFM signal parameter estimation method

Traditional parameter estimation methods of linear frequency modulation(LFM) signal based on fractional fourier transform did not deal with the contradiction between the satisfactory precision and the lesser computation cost . Therefore,a fractional domain dichotomy is proposed in this paper. Firstly, the effect of the transform order error on the parameter estimation error is analyzed and quantified. Then, the fractional domain dichotomy is adopted to obtain the optimal order of single component LFM signal corresponding to fractional domain minimum bandspread. Finally, the parameters are estimated according to the optimal order and the peak position. The parameters of strong and weak mixing multi-component LFM signal are estimated by using successive reconstruction and elimination method. Simulation results show that, compared with the traditional method, the method can meet the requirement of estimation precision with the computation cost reduced significantly.