Real-Time Calculation And Experimental Verification Of Wide-Band Radar Target Echo

With the increase of the bandwidth of radar system,bandwidth of radio frequency simulation system also increase,as well as the calculation in target simulation system.In order to save computation resources of system,researching on real-time and accurate reconstruction technology of wide-band radar target echo has important theoretical and practical significance.Firstly,the electromagnetic scattering characteristics of radar target are investigated in this thesis.And the modeling and simulation of wideband radar target electromagnetic scattering characteristics are performed.On this basis,the geometrical theory of diffraction(GTD)model is studied and used to obtain more accurate electromagnetic scattering characteristics of the wide-band radar target.Then the thesis focuses on the method of radar target scattering centers extraction based on the GTD theory,and a typical target is given as an example.Secondly,A method of wideband radar target echo signal calculation based on LFM sub-pulse is proposed in this thesis innovatively.Through dividing the LFM pulse signal into several narrow-band and short-term LFM pulses,the wide-band target echo signal of full pulse can be reconstructed by calculating the target echo signal corresponds to each sub-pulse.The thesis derived the theory of this model,and compared the requirements for the hardware resources by different methods.The simulation results demonstrate that this method can reduce the calculation dramatically and has high calculation accuracy.Thirdly,according to the research above,the real-time generation algorithm of wideband radar target echo is designed and implemented adopting Digital Radio Frequency Memory(DRFM).According to the requirement of system,an implementation based on high capacity FPGA is given.The key modules,such as orthogonal frequency modulation,parallel finite impulse response(FIR)filter are designed and analyzed in detail.Finally,the thesis carries on the experiment about wide-band radar echo reconstruction and analyzes the testing results.The results show that the method has high precision and real time capability.When the instantaneous bandwidth of signal reached 1GHz,system has a spurious free dynamic range(SFDR)performance of better than-50 dBc.