Research On Ultra-wideband Radar Imaging Technology

With the rapid development of ultra-wideband radar imaging technology,this technology has been widely used in all aspects of life.The essence of this technology is to extract and analyze the phase amplitude of the target echo in the wide-band and high-resolution characteristics of the ultra-wideband radar signal,to realize the positioning and imaging of the target.Ultra-wideband radar can locate and image targets which behind fixed obstacles.It has great potential in medical diagnosis,vital signal detection,penetration imaging,and cable inspection.Based on the NVA6100 pulse radar system,this thesis has researched on the ultra-wideband radar imaging technology.The main work is as follows:1.Firstly,research on the theory of UWB technology and radar imaging technology.Analyze the resolution of the distance and azimuth of UWB radar signals,and research on the principles of common radar positioning and imaging algorithms.Secondly,familiar with the NVA6100 pulse radar system used in my research,analyze the characteristics of the first-order Gaussian pulse signal used in the system and extract useful signals from the echo signals detected by the radar.2.Research on the analysis of radar positioning principle based on TOA estimation.Based on the characteristics of NVA6100 pulse radar,the positioning technology is slightly modified to improve the positioning accuracy of pulse radar.Research and realize single target in free space,dual target positioning in free space and single-target positioning through the wall.3.Research on the algorithm of NVA6100 pulse radar.According to the characteristics of echo signals detected by radar,the backward projection algorithm,SEABED algorithm and envelope algorithm are analyzed to realize the imaging of objects in free space and wall environment.The back projection algorithm cuts,delays,and sums the imaged regions and maps the scatter values of the points in the imaged region to the echo signals.Imaging in three different conditions was analyzed in the presence of walls.The characteristics of the system in the wall inspection are verified.The SEABED algorithm uses the polynomial curve fitting method to realize the target boundary imaging based on the quasi-wavefront data set detected by the radar,and verifies the transmission and reception isomorphism of the NVA6100 pulse radar.For the presence of walls,the analysis is based on the envelope algorithm of the transceiver splitting and transmitting and receiving the same system.4.Using the idea of synthetic aperture,the NVA6100 pulse radar with the same transceiver is transmitted and detected by multi-point detection to achieve the two-dimensional array detection effect.And the inverse boundary scattering transformation algorithm is analyzed in the two environments where free space and wall exist.The three-dimensional imaging of the target boundary is roughly realized,and the influence of the surface fitting method on the error of the three-dimensional imaging of the inverse boundary scattering algorithm is analyzed.