单通道多分量伪码复合线性调频信号分离及参数估计

Single Channel Source Separation and Parameters Estimation of Multi-component PRBC-LFM Signal

提出一种单通道内多分量伪码复合线性调频信号分离和参数提取方法。利用奇异值分解求得各分量重复周期,通过对信号求平方消除伪码对参数提取的影响,同时通过周期积累减小噪声及其余分量对待分离分量的干扰,对周期积累后的信号采用分数阶傅里叶变换(FRFT)和搜索方法估计信号调频率和载频。利用内积计算,估计分量信号的初始相位,利用伪码信号虚部为0的特性,估计出伪随机码序列及信号幅度。此外,还利用自相关矩阵特征值分解的方法估计了混合信号的信噪比,根据信噪比的不同,自适应地确定停止分解的阈值。在仿真与分析中,针对具体的信号说明了本方法的各步骤,并在不同信噪比条件下分析了该方法的有效性。

A method of single channel source separation and parameters estimation of multi-component PRBC-LFM signal is proposed. The repetition period of each component can be estimated through singular value decomposition. The influence of the pseudo code on parameter extraction is eliminated through a square calculation of signal, and the interference of noise on the component under separation is reduced by cycle accumulating. The modulation rate and the carrier frequency are estimated by using FRFT and searching the discrete points. The initial phase of multi-component signal is determined by calculating the inner product, and then the pseudo random sequence and the signal amplitude are estimated by using the character of that the pseudo random sequence is a real signal. In addition, the proposed method is used to estimate SNR of mixed signal by using eigenvalue decomposition, and SNR can be used to determine the threshold adaptively. In simulation, the method is demonstrated by separating a specific signal. The result shows that the proposed method is effective under the condition of different SNRs.