Multipath Suppression And Exploitation For Through-wall Imaging Radar

Through-wall imaging radar(TWIR)is widely used in the field of military investigation,anti-terrorism,disaster relief and other fields,to achieve the goal of life sign detection,human body location,regional imaging and other functions.The actual detection scene is usually very complex,and the signal through different paths will introduce multipath interference,leading to degradation of target extraction and imaging performance.Based on the experimental data,this paper studies the through-wall imaging algorithm,multipath propagation model,multipath suppression and exploitation methods.The application of back projection and compressive sensing technology in radar imaging is studied.The multipath interference is classified,and the echo model of the common multipath propagation in an enclosed scene is established.The multipath model is verified by simulation results based on experiment parameters.Then,the relationship between multipath illusions and true target locations is analyzed.The multipath suppression and exploitation methods are explained below.Aiming at the first-order multipath propagation model in an enclosed room,the method of locating the focusing illusion in free space and estimating the multipath ghosts region in through-wall scene is studied,respectively.According to the different antenna orientation characteristics of target and illusion,a multipath suppression method based on sub-aperture imaging and image fusion is proposed.Then,a multipath utilization method based on target-ghost association is studied.Application and complexity performance of the two methods is analyzed,and the effectiveness of the methods is tested with simulations and experiment results.Based on the compressive sensing reconstruction technique,the sparse model of the multipath signal is analyzed.A multipath suppression method based on different measurement space reconstruction is then proposed.The original target space is respectively reconstructed by target and multipath measurement matrix,and the multipath interference can be eliminated effectively.For the case of point target and extended target model,a multipath exploitation method based on joint sparse reconstruction is studied.Finally,the performance of the two methods above is tested using simulations and experiment data.In this paper,the theoretical research on the use of multipath echo components and the ghost suppression in an enclosed scene is discussed.The key problems such as the applicable scene and performance of the proposed methods are discussed.The proposed methods verified with simulations and experiment data have great engineering significance,and they lay the foundation for the follow-up research on the areas of multipath suppression and exploitation.