A Controllable Active Jamming Method Against SAR Based on Secondary Modulation

Due to the weakening effects on the reconnaissance and detection ability of target imaging radar system, SAR jamming has attracted wide attentions in the research field of electronic countermeasures. Generally, SAR jamming methods can be mainly classified as suppression jamming and deceptive jamming based on the generated jamming effects. The suppression jamming methods are easy to implement but have the problems of high power demand and limited jamming effects. The deceptive jamming methods can realize rich jamming types but have the problems of high demand of parameter reconnaissance precision and algorithm complexity. Hence, it is urgent to study easy-to-implement, flexible, and controllable jamming methods to cope with the increasingly complex electromagnetic countermeasure environment. Based on this, a controllable active jamming method against SAR system based on the secondary modulation is proposed in this paper. This method first performs range periodic phase modulation, range sine function modulation and range shift-frequency modulation on the intercepted SAR signals, then further performs azimuth periodic phase modulation, azimuth sine function modulation and azimuth shift-frequency modulation so as to generate the desired jamming signals. This method combines the periodic phase modulation with the sine function modulation to achieve both the suppression jamming effects and the deceptive jamming effects. Through changing the modulation parameters, nine different types of two-dimensional jamming effects can be generated. Meanwhile, the jamming coverage and the jamming position can be accurately controlled. Finally, the correctness of proposed theoretical model is validated by the jamming simulations based on the airborne SAR original echo data.