利用子带提取改善信号检测能力

对低截获概率(LPI)信号和低观察率目标检测的要求越来越高,在低信噪比下检测信号的方法也越来越受到关注。提出了一种基于小波变换的信号子带提取方法。在周期谱估计之前用小波进行信号分解,确定信号所在的子带,从而达到去噪的目的。同时提出相关法与周期谱估计相结合的方法,并证明该方法可进一步改善信号的检测能力。以电视发射信号的无源相干定位系统的回波信号和相位码信号为例进行了仿真实验。仿真结果表明,这种方法能在-21dB信噪比(电视信号)和-24dB信噪比(相位码信号)下检测出信号。

Improvement of signal detection ability based on subband extraction

The demand for detection of objects with low probability of interception (LPI) and low observation rate is increasingly high. The method of signal detection in low signal-to-noise ratio (SNR) has been widely concerned. An extraction method of signal subband based on wavelet transform is provided. The signal is resolved using wavelet before periodic spectral estimation, and signal subband is determined for the purpose of removing noise. In the meantime the correlation algorithm is combined with periodic spectral estimation, and a further improvement of the signal detection ability using this method is proved. The simulation test of the echo signal of passive location system which signals are transmitted by TV station and the phase coded signal is performed. The simulation results show that this method can detect a TV signal at - 21 dB (SNR) and a phase coded signal at - 24dB (SNR).