运动干扰站的SAR-GMTI余弦调相转发干扰

Cosinusoidal phase-modulated repeater jamming to SAR-GMTI based on a moving jamming station

针对多通道合成孔径雷达地面动目标显示SAR—GMTI提出一种基于运动干扰站的余弦调相转发干扰方法。该方法利用运动干扰站转发式干扰的成像特性实现方位向扩展,利用余弦调相信号特性实现距离向扩展,将二者有机结合,可同时实现干扰目标在方位向和距离向的2维扩展。以三通道干涉对消技术为例分析了其对GMTI的对抗性能,理论分析和仿真实验表明:该方法对SAR和SAR-GMTI均可产生灵活可控的2维条带状或面状遮盖干扰效果,但由于多通道GMTI对干扰的抑制和对消,干扰目标幅度受正弦调制系数影响将出现增强或削弱。

Synthetic Aperture Radar （SAR） is an all-day, all-weather high-resolution senor that has been widely used in civilian mapping, military investigation, and strategic reconnaissance. Ground Moving Target Indication （GMTI） can detect and track moving targets, and obtain their moving information, which has been an important application of SAR for ground moving target detection and imagery. SAR, which has GMTI capability, can obtain focused stationary target images and moving target information at the same time, and form a more detailed battlefield map. Thus, it has increasingly become an important part of battlefield surveillance and strategic reconnaissance systems. Jamming technology research against SAR-GMTI has been an issue in the area of electronic countermeasures because of the growing threat of SAR-GMTI systems to important military moving targets. SAR-GMTI systems typically use multiple channels to suppress cluttering and jamming. Thus, traditional jamming methods for SAR are usually invalid for SAR-GMTI systems. In this paper, a new jamming method for multi-channel SAR-GMTI is proposed; this method is cosinusoidal phase-modulated repeater jamming based on a moving jamming station. First, the imaging feature of repeater jamming of a moving jamming station is analyzed by the principle of stationary phase and is used to realize azimuth jamming extension. At the same time, the cosinusoidal phase-modulated signal model is proposed and used to realize range jamming extension, thereby enabling their combination to realize two dimension jamming extension in range and azimuth. Second, the jam- ming performance of the proposed method for SAR is analyzed thoroughly, and the relationship between jamming parameters and perform- ance is obtained. Then, the countering performance against SAR-GMTI is analyzed by using the cancelling technique of tri-channel interfer- ence ,and the cancelling output expression of the final interference is derived. Finally, the simulation experiment and application example are presented. Computer simulation and theoretical analysis show that the method can produce flexible and controlled two dimension banded or planar-covering jamming performance for SAR and SAR-GMTI. Moreover, because of interference suppression and cancellation of multi-channel GMTI, the amplitude of false targets is affected by sinusoidal modulation coefficient, thereby revealing enhanced and weakened areas. The proposed method is simple, flexible, and controllable. Compared with the deceptive jamming method, its dependence on reconnaissance is lower; and compared with the traditional barrage jamming method, its jamming signal power requirement is lower because of the high two dimension coherent processing gain. The method can protect stationary and moving ground targets at the same time, thereby effectively strengthening the countering performance for multi-channel SAR-GMTI systems. Moreover, the method has important military application value.