基于FRFT模最大值的LFM信号参数估计方法

Estimation Method of LFM Based on Fractional Fourier Transform

提出了一种基于分数阶Fourier变换模最大值的LFM信号参数估计方法,先对线性调频信号以较大的间隔先进行FRFT模变换,寻找次次最大值和次最大值点。在这两点之间以较小的间隔再进行FRFT模变换,此时寻找最大值点所对应的变换阶数即是最佳变换阶数,由量纲归一化即可得到LFM信号的调频斜率。提出的两次搜索最佳变换阶数法相比于传统方法不需要二维搜索,在相同的计算精度条件下大大降低了计算量,提高了效率。

The paper proposes an estimation method for linear frequency modulation（LFM）signal detec-tion based on the fractional Fourier transform（FRFT）.First FRFT is performed on LFM signal in big inter-val,and then the hypo-maximum and tertiary maximum are found.Lastly FRFT is performed on LFM signal in small interval.Now the angle corresponding to the maximum is the optimal angle.The frequency modula-tion of the LFM can be gained from dimensional normalization.The twi-searching method doesnt need planar search,consumedly reducing the computation cost at the same precision.