被动探测中相关时延估计研究

Research on correlation time-delay estimation for passive detection

被动探测具有反侦察、抗干扰及隐蔽性强等优点,成为当前提高电子对抗能力的一个非常重要方向,被动探测的关键技术之一就是通过有效的信号处理方法提取出多接收器的时间差,确定时差最基本的方法是进行信号相关来获得估计信息,相关算法虽然计算过程简单,但是算法对信号和噪声频谱特性要求比较高。对信号的互功率谱密度函数进行频域加窗,抑制噪声功率,使得信号噪声白化,增强信号中信噪比高的频率成分,从而提高估计的精度。

Passive detection has the advantages of anti-reconnaissance,strong anti-jamming and concealment.It has become an important direction to raise the capacity of electronic countermeasures.One of the key technologies for passive detection is to extract the time lag through effective signal processing.Relevant method is the most basic information to estimate the time difference.It is basic theory of all correlative time-delay estimation algorithms.Calculation correlation method is simple.But good results cannot be achieved if the spectrum characteristics of signal and noise not ideal.Make a window function on the cross-spectral density function to restrain the power of noise and whiten the noise.The method enhance the component whose SNR are high and improve the estimate precision.