Radar Active Interference Suppression Algorithm Research

Radar systems are important electronic equipments for the modern warfare, which detect targets by using electromagnetic waves. With the development of radar electronic countermeasures (ECM), the radar electronic counter countermeasures (ECCM) causes widespread attention at home and abroad as an important factor that affecting the survival of radar.The typical pulse compression (PC) radar system, which sends the linear frequency modulation (LFM), is taken as our research object. Aiming at promoting the anti-jamming capability of radar, we study the active interference suppression technology. In this thesis, the author focus on the suppression technology of active additive compound jamming and smart noise jamming, and validate the conventional active jamming suppression algorithmic. This thesis has principally conducted study in the following aspects:First, the mechanism of generation and action of the active jamming, which include conventional active jamming, active additive compound jamming and smart noise jamming are studied. Active additive compound jamming and smart jamming had been taken as the most important research object. In this chapter, The characteristics of the signals are analyzed, and their time domain expression and interference performance is studied also.Second, for the active additive compound jamming, an algorithm which is based on the phase-perturbed theory is studied. Take the characteristics of LFM signal into account, the jamming can be restrained by change the radar transmit signal to Slope-Varying LFM (SV LFM), and use jamming pulse compression to strengthen the jamming signal, then give the results of pulse compression a "punish" , and finally the echo signal can be restored by the previous pulse match filter.Third, taking the generation mechanism of additive compound jamming into account, the step to step suppression algorithm is studied. This algorithm is practical, because the conventional active jamming restrain method can be used. The disadvantage of this algorithm is that the class of the components of the jamming must be known at first, to resolve this, some jamming recognition methods and selection of radar electronic counter countermeasures is need to be added in the radar system.Fourth, an algorithm, based on LFM stretch processing, is studied to suppression the smart noise jamming. With a special reference signal, the target echo can be move to the low frequency, and the false target signal will be take a wide band frequency in frequency domain. Thus, a wave-trap technique can be utilized to cancel the jamming signal and then the target echo can be rebuild.Fifth, construct a simulation platform that similar to the actual situation, and use the simulation platform to validate the existing conventional active interference suppression algorithm. Taking confidentiality and the gap between simulation parameters and reality into account, simulation platform is constructed by adjust the actual parameters of and a certain type of radar and blanket jammer and deception jammer. Simulation of the jamming suppression algorithms include: noise frequency modulation (FM) jamming suppression algorithm based on the elimination of jamming, and a radar false targets suppression algorithm based on Stretch LFM treatment.