Research On Jamming Technology Against Space-time Two-dimensional Processing

Space-time adaptive processing(STAP)technology is a key technology for clutter suppression and target detection of a new generation of airborne early warning radar and airborne down-looking radar.By combining with a phased array system,it has superior clutter suppression performance and anti-jamming capabilities.In the electronic warfare environment,it poses a serious threat to our important military objectives.Therefore,actively researching effective interference methods against STAP technology has important military significance for radar opponents.Based on the basic principles of STAP technology,this thesis studies the Doppler dimensional interference method against STAP and the Doppler-azimuth two-dimensional interference method against STAP,aiming at the weaknesses and limitations of the technology.The research work of this thesis mainly includes the following three parts:Firstly,the basic principles of STAP technology are studied.Starting from the actual working environment of the airborne radar in the front-side working state,the array antenna model and the target,noise,clutter,and interference echo signal models of the airborne rad ar are established in this thesis.Based on the data model of wave signal processing,the space-time characteristics of airborne radar clutter are briefly analyzed through the clutter power spectrum and clutter characteristic spectrum.In addition,the model structure of the optimal STAP processor and the basic principle of the SMI algorithm are introduced.These basic theories of space-time adaptive processing provide a theoretical basis for the research of STAP interference technology.Secondly,the Doppler dimensional interference method against STAP is studied.After improving the traditional single interference pattern,this thesis proposes three new composite interference methods,including: frequency-shift interference based on periodic square wave convolution,step-by-step frequency-shift interference based on delay superposition,and intermittent sampling cycles forward interference based on noise convolution.For the three interference methods mentioned above,the interference signal models are established and analyzed by simulation experiments.The simulation results show that compared with the traditional interference methods,the three new composite interference methods proposed in this thesis can generate more false target groups with more random amplitude distribution.The introduction of these false target groups can significa nt ly improve the interference effect on the STAP Doppler dimension,which causes the target detection performance of the STAP processor is severely degraded.Thirdly,the Doppler-azimuth two-dimensional interference methods against STAP are studied,including multi-azimuth dense interference,and space-time joint domain interference based on corner reflector.Among them,the multi-directional dense interfere nce method uses multiple noise suppression jammers to interfere with the main lobe of the radar equipped with the STAP system,which can consume a large amount of system freedom of the STAP processor,resulting in a significant lack of system freedom reserved for target detection,which in turn affects the target detection performance of the STAP processor.The space-time joint domain interference method based on the corner reflector can interfere with the target echo signal to form an angle deception mechanism based on the interference signal reflected by the corner reflector.By arranging several corner reflectors with differe nt azimuth information and Doppler information from the real target on the ground,false spacetime two-dimensional information can be generated in the space-time two-dimensio na l power spectrum,which has a deceptive interference effect on the STAP processor.Based on the passive interference of angular reflectors,this thesis proposes an active-passive coordinated interference method.By adding active interference at the azimuth where the target and corner reflector are located,it can also form a masking interference effect at the Doppler dimension of the corresponding azimuth.For the above interference methods,the corresponding interference generating principles are analyzed in this thesis,and the correctness of the theoretical analysis and the effectiveness of the interference methods are verified by simulation experiments.