Echo Modeling And Moving Target Integration Method For Wideband Missile-borne Radar

With the constant changes in the modern battlefield environment,ultra-low-altitude penetration weapons have become a major threat to the national defense system.The missile-borne radar is one of the effective combat weapons of this type of target.However,due to the multipath effect generated by the ultra-low altitude target,both the target and the multipath signal are present in the echo signal,which poses a challenge for target recognition and tracking.Moreover,due to the high speed and high maneuverability of the target,a large radial velocity and radial acceleration are generated between missile and target.The resulting distance migration and doppler migration have a bad influence on the coherent accumulation of echo signals,which seriously reduces the detection performance of coherent accumulation.Aiming at these problems,this thesis proposes a modeling method for ultra-low altitude targets and multipath of wide-band missile-borne radars,and then studies the coherent integration methods for uniform and uniform acceleration targets.The main work is summarized as follows:(1)The multipath effect,geometric configuration and ground surface scattering characteristics of ultra-low altitude targets are studied.An ultra-low altitude target and multipath echo signal model is proposed.Based on the analysis of the multipath effect generated by the detection of ultra-low altitude targets,the ultra-low altitude targets and multipath signal propagation geometry are established,and the scattering regions of the ground surface are divided on this basis.The scattering coefficient of each scattering block is obtained by the Barton/Morchin model,the idea of double-base radar equivalent to single base radar,and the reflection coefficient corresponding to the Brewster effect.According to the radar equation and the scattering coefficient of the scattering region,the ultra-low-altitude target and multipath echo modeling received by the radar are calculated.respectively.The theoretical analysis results are consistent with the actual simulation results,which verifies the effectiveness of the proposed modeling method.The proposed method is more accurate than the statistical method because it considers the scattering coefficient of the radar equation.In addition,the method considers the Brewster effect and is more in line with the physical characteristics of the sea clutter.(2)For the range migration of uniform moving targets,the coherent accumulation method of uniform moving target in wide-band missile-borne radar is studied.The Keystone transform algorithm and the RFT algorithm are studied,and the basic principles and their fast implementation methods are introduced respectively.Aiming at the doppler ambiguity problem of fast moving targets,a matching filter function is proposed to eliminate doppler ambiguity.The simulation results show that the complexity of the two algorithms can be greatly reduced by CZT-FFT,and the effectiveness of the algorithm are verified.(3)Aiming at the Doppler migration of uniformly accelerating moving targets,the coherent accumulation method under wide-band missile-borne radar is studied.A TRT-SIAF-MSCFT algorithm is proposed to estimate the CF-CR of slow-time signals.By adjusting the scaling factor of MSCFT,the algorithm can estimate the parameters of arbitrary pulse repetition frequency and acceleration;the CF spectrum ambiguity problem is effectively solved by the TRT algorithm.The MSCFT operation can be quickly implemented by using CZT,which greatly reduces the amount of computation.The simulation results show that the proposed algorithm can effectively distinguish the target and multipath signals and accurately focus on the distance and Doppler domain,and verify the accuracy of the algorithm for estimating the acceleration of the ultra-low altitude target.