基于频域相位方差加权的线性调频信号检测方法

针对未知线性调频信号的检测问题,依据线性调频信号相位比较稳定这一特征,提出一种基于频域相位方差加权的线性调频信号检测方法。该方法利用线性调频信号频率单元对应相位比较稳定,背景噪声频率单元对应相位比较随机的特点,对各频率单元进行相位方差加权,可以进一步抑制背景噪声能量干扰,增强线性调频信号检测信噪比增益,实现对未知线性调频信号的检测。仿真条件下,在输入平均谱级比大于-10 dB时,相比相位差分对齐法,该方法所得最终线性调频信号频率单元与噪声频率单元的平均谱级比得到了进一步提高,且随着输入平均谱级比越高,输出线性调频信号频率单元与噪声频率单元的平均谱级比提高越多。理论分析和实验结果表明:该方法可以有效增强信号能量,抑制噪声,提高信噪比。

Detection method of linear frequency modulated signal based on frequency domain phase variance weighting

Concerning the problem of detecting unknown Linear Frequency Modulated (LFM) signal, according to the feature that the phase of the signal is stable, a LFM signal detection method based on the frequency domain phase variance weighting was proposed. The proposed method utilized the characteristics that the phase of LFM signal frequency unit was stable, and the phase of noise frequency unit was random, to weight each frequency unit by the phase variance, which could further restrain the background noise energy disturbances, enhanced the Signal-to-Noise Ratio (SNR) gain of signal detection, and achieved detecting unknown LFM signal. Under simulation conditions, when the input average Spectrum Level Ratio (SLR) was greater than -10 dB, compared with phase difference alignment method, the output average SLR of the proposed method was further improved, and with the input the average SLR became higher, the output SLR was further improved. The theoretical analysis and experimental results show that the proposed method can well enhance the energy of LFM signal, restrain the background noise energy, and improve SNR.