基于分数阶字典的间歇采样转发干扰自适应抑制算法

间歇采样转发干扰是一种对现有体制雷达具备高度威胁的新型干扰,典型样式包括间歇采样直接转发干扰、间歇采样重复转发干扰和间歇采样循环转发干扰。干扰信号与真实回波时频域、分数阶域混叠,常规信号处理方法难以做到有效分离。针对该问题,分析了3种干扰样式时域、最优分数阶域特征,构造了两种分数阶正交字典,即分数阶大字典和分数阶联合字典,区分弱干扰背景回波信号和强干扰背景回波信号,采取不同的干扰抑制方法,从而构建了基于分数阶字典的间歇采样转发干扰自适应抑制算法。仿真结果表明,所提算法适用强弱干扰背景,弱干扰背景下恢复信号与真实回波相似度更高,强干扰背景下恢复信号信噪比(signal to noise ratio, SNR)损失更低。

Interrupted-sampling repeater jamming adaptive suppression algorithm based on fractional dictionary

Interrupted-sampling repeater jamming is a new type of jamming, highly threatening the existing radar systems. The typical patterns include interrupted-sampling direct forwarding jamming, interrupted-sampling repetitive forwarding jamming and interrupted-sampling loop forwarding jamming. For the reason of the overlap in time-frequency and fractional domains, it is difficult to separate the target echo from the jamming signal by conventional signal processing tools. To solve the problem, the characteristics of the three kinds of jamming signals in time domain and optimal fractional domain are analyzed, and two kinds of fractional orthogonal dictionaries are constructed, i.e., fractional big-dictionary and union-dictionary. Different jamming suppression methods are adopted under weak or strong jamming backgrounds. An interrupted-sampling repeater jamming adaptive suppression algorithm based on fractional dictionaries is proposed.The simulation results show that the proposed algorithm is suitable in different jamming backgrounds, the recovery signal is more similar to the target echo under the weak jamming background, and the loss of signal to noise ratio (SNR) of the recovery signal is lower under the strong jamming background, compared to other methods.