Research On Jamming Method To Airborne Radar STAP

Nowadays,space-time adaptive processing(STAP)has become a key technology and an important measure for airborne radars to detect moving targets.It poses a great threat to our moving targets in the battlefield environment.Therefore,the research on interference technology to STAP has become an important research content in the field of electronic countermeasures.The work of this thesis is carried out in two aspects: one is to study the principle of STAP algorithm and its simulation,and the other is to inject interference into airborne radar system and analyze the effect of interference.The main work of this thesis is as follows:1.The airborne radar system and its signal processing flow are studied.The signal environment of the airborne radar system is modeled and analyzed.Based on the space-time characteristics of the target echo,clutter,noise and interference,two-dimensional steering vector models are established respectively.By simulating the power spectrum of the signal environment,the rationality of the model is verified.2.The working principle of STAP is studied.STAP achieves the purpose of suppressing clutter and detecting targets by dynamically adjusting the two-dimensional filter and selfadaptively forming deep vertical nulls matching with clutter in the space-time twodimensional plane.The full STAP algorithm is simulated and analyzed.For the defects that full STAP algorithm requires large amount of training samples and calculation,two kinds of dimensionality reduction algorithms are studied: m-DT dimensionality reduction algorithm and Joint-domain Localized(JDL)dimensionality reduction algorithm.The dimensionality reduction algorithms reduce sample requirements and improve processing efficiency.Based on the analysis of simulation results,the performance of the three algorithms is compared and analyzed.3.Radar interference patterns and interference signal models are established.According to the characteristics of STAP,combined with the characteristics analysis of the interference signal,three possible types of interference signals are proposed: noise convolution interference signal,delay forwarding interference signal and random frequency shift interference signal.These three interference signal patterns are simulated separately.The matching filtering results and the MTD results of the target echo superimposed interference signal verify the feasibility of the interference signal patterns.4.Based on the confrontation conditions,a variety of confrontation scenarios are established,and different interference signals are injected into the airborne radar.The interference performance of various interference patterns on STAP are analyzed based on the analysis of the airborne radar STAP target detection performance under different scenarios and different interference signal patterns.According to the simulation results,the following conclusions are obtained:(1)Under the self-defense interference scenario,both the noise convolution interference and the delay forwarding interference have good interference effects on airborne radar STAP,and the target signal is suppressed.(2)With the team interference scenario,random frequency shift interference can achieve deception jamming to the airborne radar STAP,so that the radar obtains wrong target information.(3)When the degree of freedom of distributed interference is large enough,STAP will suffer a decrease in performance due to lack of sufficient system freedom.