基于多路欠采样的多分量LFM信号参数估计

针对多分量线性调频(Linear frequency modulated,LFM)信号，提出了一种基于多路欠采样的参数估计方法。采样过程由多个采样速率相同、采样时刻不同的模数转换器实现，总采样率可以低于信号的奈奎斯特采样率。基于欠采样序列乘积型模糊函数的单频特性，可以通过峰值检测实现调频斜率的估计。根据估计出的调频斜率对各路欠采样序列进行解线调处理，可得到多频正弦信号。结合矩保持问题的求解方法以及对超定方程组的求解，可以根据解线调后的各路序列估计出原始LFM信号各分量的初始频率。本文方法能够根据亚奈奎斯特采样样本实现LFM信号的参数估计，并且运算简单、易于实现。仿真实验验证了其有效性和准确性。

Parameter Estimation of Multi-component LFM Signal with Multiple Subsampling Channels

A parameter-estimation method based on subsampling for multi-component linear frequency modulated (LFM) signal is proposed. The received signal is subsampled by multiple analog to digital converters (ADCs) with identical sampling rate and different sampling time. The total sampling rate of all ADCs is lower than the Nyquist rate of original LFM signal. As the product ambiguity function of a single subsampling sequence is a single tone, the chirp rate is estimated by searching for the peak of the product ambiguity function. Then dechirp operation is conducted for all subsampling sequences to obtain multitone signals, from which the initial frequencies of LFM components are estimated by solving moment-preserving problem and over-determined equations. In the proposed method, parameters of the LFM signal are estimated from sub-Nyquist samples, and the estimation is easily realized with simple operations. Simulation results verify the effectiveness and accuracy of the proposed method.