间歇采样转发式干扰是一种新型电子对抗方法,针对线性调频(LFM)体制雷达,干扰机采样并转发部分雷达发射信号,形成与目标回波相干的干扰信号,从而在对方雷达接收机匹配滤波过程中形成多个虚假的目标尖峰。为了对抗此干扰,文中提出了一种正负斜率LFM对消法,该方法使用数字阵列雷达在不同的天线单元同时发射正负调频斜率的 LFM 信号。 由于正负调频斜率 LFM 信号中的间歇采样转发式干扰回波同时到达,所以具有相反调频斜率的干扰回波被分离、去斜,再调整两个信号之间的频率差和相位差,就可通过两个信号相减来达到对消干扰并保留目标信号的目的。仿真结果表明:采用正负斜率 LFM 对消法,在20 dB的干信比下,间歇采样转发式干扰的功率被抑制了28 dB。

The interrupted-sampling repeater jamming is a newly emerging electronic countermeasure method. For linear frequency modulated (LFM) radar, part of the radar emission signal is sampled and then forwarded by the jammer, forming jamming signal coherent with the target echo. Multiple false target spikes are formed during the process of matched filtering in the victim radar receiver. To combat the jamming, a double-LFM method is proposed in this paper which uses digital array radar to simultaneously transmit positive and negative chirp rate LFM signals in different antenna cells. As the interrupted-sampling repeater jamming echoes arrive at the same time for the positive and negative LFM signals, the jamming echoes with opposite rates are separated and dechirp processed. After adjusting the frequency difference and phase difference between two signals, the purpose of canceling jamming and retaining the target signal is achieved by subtracting two signals. Simulation results demonstrate that using the doubleLFM method, the power of interrupted-sampling repeater jamming is suppressed by 28 dB under the condition of 20 dB jamming-tosignal ratio.

TN972