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频谱弥散(Smeared Spectrum,SMSP)干扰是一种针对线性调频信号的相参压制干扰。根据SMSP干扰子脉冲的周期特性,提出了一种基于干扰重构和峭度最大化的干扰抑制方法。首先,利用自相关方法估计干扰子脉冲的周期,并根据干扰的产生原理确定子脉冲调频斜率,即可重构相位未知的干扰子脉冲。其次,对重构的子脉冲分别设定不同的相位,并与接收信号做共轭相乘,根据相乘的结果确定干扰信号的初相位。最后,利用峭度最大化原理,确定干扰抑制因子,实现干扰抑制。仿真结果表明,该方法能够有效实现干扰抑制,经过干扰抑制后的信干比可达20dB以上,并且在存在噪声和相位误差的情况下,仍能够保持较高的信干噪比增益。
Smeared Spectrum (SMSP) interference is a coherent suppression interference for a chirp signal. According to the periodic characteristics of the SMSP interference sub-pulse, an interference suppression method based on interference reconstruction and kurtosis maximization is proposed. Firstly, the period of the interfering sub-pulse is estimated by using the autocorrelation method, and the sub-pulse frequency modulation slope is determined according to the principle of the interference, so that the interfering sub-pulse of unknown phase can be reconstructed. Secondly, different phases are set for reconstructed subpulses, respectively, and then conjugate with the received signal to obtain the initial phase of the interference signal according to the result of the multiplication. Finally, the kurtosis maximization principle is used to determine the interference suppression factor to achieve interference suppression. The simulation results show that this method can effectively suppress the interference, and the signal-to-interference ratio can reach more than 20dB after the interference suppression. And the signal-to-interference-plus-noise gain can still be maintained in the presence of noise and phase error.