Study On Simulation And Target Detection Method Of Ultra-Wideband Through-Wall Radar

Urban combat,anti-terrorism,post-disaster relief and many other aspects have the needs of detecting targets behind the obstacle.Compared with other penetration detection technology,ultra-wideband through-wall radar system has a significant advantage,its work is not subject to visual conditions,environmental changes,weather changes and other factors.In this paper,the ultra-wideband through-wall radar system is simulated by electromagnetic simulation algorithm,and then the detection of targets behind the wall is carried out.The mechanism of ultra-wideband penetrating wall radar system is mainly classified as impulse system,stepping frequency system and linear frequency modulation system.This paper studies the ultra-wideband through-wall radar system based on the impulse radar system.Firstly,the working principle of through-wall radar imaging is introduced,the mathematical model of the wall is established,and the influence of the wall on the radar signal is deduced.The expression of the.radar echo signal.and the method of removing the jamming signal in the echo signal are given by using the narrow pulse UWB signal.Electromagnetic simulation was performed by using time domain finite difference method(FDTD).FDTD is an approximate solution to the Maxwell equations.In this paper,three points of FDTD algorithm are introduced:differential form transformation of Maxwell equations,stability condition of solution,and absorption boundary condition.Based on FDTD algorithm,the electromagnetic simulation model of UWB radar system is established.The relevant parameters of the simulation model and the related software of signal processing are given.The triangular positioning and backward projection algorithms are studied.The transmission process of radar transmitting signal in free space and wall is studied and compared respectively.According to the influence of the wall on the algorithm,the algorithm is modified in the environment of existence of the wall.The detection of single point and multi-point still targets is studied,and the simulation results are given.The study of moving target is carried out,and the simulation is carried out,and the trajectory of the target is drawn.A simple simulation of life detection of ultra-wideband through-wall radar is carried out,and the simulation results are given.Both of the above two imaging algorithms need to obtain the wall parameters(thickness and relative dielectric constant of the wall)in advance,but it is hard to do this f in practical applications.For the case of unknown wall parameters,two solutions are proposed:First,analyze the influence of wall parameters on the target position,generate the target position curve according to the change of the position of the target under different parameters,and find the intersection of the curves under different configurations.The second solution is to estimate wall parameters based on the difference of reflection signals on both sides of the wall.The estimation algorithm of the above two methods is given,and the simulation research is carried out.The results show that both of these methods are effective.Finally,the paper summarizes the research work,and analyzes the next step of the improvement and in-depth research for the future.