低信噪比下LFMCW信号调频参数估计

parameter estimation of LFMCW Signals under low SNR

随着雷达技术的不断进步,线性调频连续波信号作为一种应用广泛的低截获概率雷达信号,常规的信号参数估计方法对其很难凑效。本文针对LFMCW信号时频分布的特征,利用离散线性调频傅里叶变换,同时结合相干平均的算法,有效估计信号的载频和调频斜率。通过理论分析并结合仿真实验对LFMCW信号的两种主要信号形式——锯齿波调制和三角波调制信号进行仿真实验,结果表明提出算法的正确性和在低信噪比下仍具有较高的估计精度,具有较大的工程应用价值。

With the continuous progress of radar technology, Linear Frequency Modulated Continuous Wave（LFMCW） signals has been widely used as Low Probability of Intercept signal. The performance of conventional methods decreases rapidly, even invalid. This paper deals with the parameter estimation of LFMCW signals, aiming at the time frequency distribution characteristic of LFMCW signals, the method based Discrete Chirp-Fourier Transform（DCFT） and coherent average which can estimate the carrier frequency and frequency modulate rate is proposed. Theoretical analysis and simulation results of the two types of LFMCW signals which including symmetrical triangular LFMCW and sawtooth LFMCW, indicate that the presented algorithm has higher estimation accuracy under the low SNR. And it has important theory significance and the military application value.