Research On Radar Feature Of Human Micro-motion In Terahertz Band

Research on radar feature of human micro-motion can be widely applied to security checks,counter-terrorism and battlefield detection etc.Among them,the bands of terahertz(0.1~10THz)radar works between the millimeter-wave and infrared-wave,in thus case,it has both the advantages of them.On the one hand,the wavelength of terahertz is shorter than microwave,increasing the micro-Doppler effect of the target.It can depict the characteristics of target micromotion precisely.On the other hand,compared with infrared band,the terahertz wave can penetrate the smoke,dust and particle easily.The main research content of this paper includes: pedestrian movement model,characteristics analysis of smooth and rough pedestrian micro-doppler on terahertz band,parameter estimation of human micro-mition.Firstly,this papaer analyzes research background and significance on radar feature of human micro-motion in terahertz band.Then if introduces the development status quo of terahertz radar and radar characteristics of human motion.Eventually,it puts forward the main contents and schedule.The second chapter studies the pedestrian micro-motion model.Based on the fundamental human micro-motion model-the rotational movement,it analyzes the rotation model of point target and its micro-doppler characteristics.According to H-Anim human body model,this chapter consturcts a line structure manikina with ten freedom degrees in joint.Furthermore,it studies the periodic model of pedestrian movement and the variation model on freedom degree of joint during the movement process.Finally,it anylyzes the swing distance model of the large arm,small arm,thigh,leg and foot according their movement law.In the third chapter,the micro-doppler characteristics of pedestrian in terahertz band are studied.A smooth line structure of the pedestrian radar echo model and a rough line structure of the pedestrian radar echo model are established respectively.By using STFT method,in 220 GHz,140GHz and 12 GHz respectively,it analyzes micro-doppler characteristics of smooth and rough line structures manikin,distinguishing the differences of the micro Doppler features between the microwave and terahertz frequency,among the terahertz frequency,and between the upper and lower limbs.At last,the differences of the results of the two cases of smooth and rough motion were compared.The fourth chapter studies the parameters estimation of pedestrian micro-motion in terahertz band.Firstly,it calculate the periodic parameter by means of the auto-correlation method.Then,other parameters can be estimated by nonlinear least squares method based on Gauss-Newton.According to the model of pedestrian movement in the smooth and rough conditions,the estimation function model and the corresponding parameter vector of the estimated parameters are derived.In the estimation of the distance between human and radar,the initial value is given by the method of wideband radar ranging.In case of the irreversible problems of Jacobian matrix in rough pedestrian model,it modifies Gauss-Newton iterative step according to the priori information.At last,the main contents and innovations of this paper are summarized,and the problems and the direction of the research are pointed out.