Research On UWB Detecting Technique Based On TRM Model

The detection of concealed target has been one of the most important subdivisions andbooming realms of radar technology. It can be utilized in municipal pipeline detection,geological prospecting, non-destructive testing of transportation facilities, militaryreconnaissance mission and life searching and rescuing, etc. Therefore, whether in civilian ormilitary domains, the technique of detecting concealed target shows broad developmentprospects and great application value.UWB (Ultra Wideband) detection is an emerging technology in21stcentury. Comparedwith the traditional narrowband signal, UWB signal can meet the requirements of detectingdistance and resolution, with strong penetrability and high resolution. For this reason, it isincreasingly applied in fields of detecting and imaging.TRM (Time Reversed Mirror) is a combinative method of wave transmission theory inphysics and array processing technology. It makes effective use of the reciprocity principle ofelectromagnetic field and the physical process of multipath transmission, taking multipatheffect from adverse factor into favorable factor. In this way, ambient orientation andresolution of the system is enhanced. As a result, TRM technology demonstrates greatpotential in the application of detecting concealed target.This paper presents a UWB detecting system based on TRM model and discusses thewaveform selection. It also analyzes the system performance and builds some relevantsimulations. Then optimization proposals are provided in aspects of waveform designing anddetecting method. The main works of this dissertation are summarized as follows:1,Briefly introduce the study background and basic theory of UWB detecting and TRMtechnique. Propose a system framework using both UWB and TRM technology. Thendescribe the working procedure and the mathematical model of the system.2,Select a proper form of the detecting signal, considering the system performance,radiation efficiency of the antenna, penetrability of the signal and system resolution.3,Present the analyses and simulations about the system performance of multipathcompensation, self-focusing, adaptive channel equalizing and super-resolution.4,Improve the signal performance by pseudo-random pulse position modulation.Analyze the affection of modulation parameters on smoothness of the power spectrum and theanti-RFI ability. Then summarize the main points about setting modulation parameters. 5,Provide optimization proposals on TRM detecting, aiming at targets hidden beneath aninterface and in multi-scattering environment. For the former one, time-window method,transposed receiving method and mean-offset method are proposed. For the latter one,iterative-TRM algorithm is introduced.