基于Duffing振子的弱Chirp信号检测与参数估计

在超低信噪比下, 针对 chirp 信号常规检测方法均失效. 提出一种超低信噪比下 chirp 信号的检测与参数估计方法. 该方法利用 Duffing 振子构建广义滤波器组,并以其最大 Lyapunov 指数的符号作为系统状态的判断标准. 根据 chirp 信号的特征, 将 chirp 信号的检测问题转化为一个周期信号检测的问题, 使其满足 Duffing 振子的检测条件. 获得调频斜率的估计后, 构造一个新序列, 再利用 Duffing 振子系统估计初频. 为提高信噪比, 本文还提出分段相关平滑的方法, 使检测和估计性能得到提高.

Detection and Parameter Estimation of Weak Chirp Signal Using Duffing Oscillator

In the case of ultra-low signal-noise-ratio(SNR),the conventional methods for chirp signal detection are invalid.An algorithm for weak chirp signal detection and parameter estimation is presented in this paper.The generalized filter array is constructed using a Duffing oscillator,and Lyapunov exponential is exploited to judge the state of the system. According to the characteristics of the chirp signal,the problem of chirp signal detection is transformed into a periodic signal detection problem to meet the demand of Dnffing oscillator system.After the chirp rate is estimated and a new sequence is constructed by the corresponding processing,the starting frequency is estimated using the Duffing oscillator system again.Moreover,a segmented correlation smoothing method for enhancing the SNR is proposed to improve the performance of the method.