The Research On Multi-stationary Targets Imaging Method Under The Indoor Environment Using TWRI

UWB-TWRI could complete the non-invasive detection by exciting an extremely short duration pulse signal to penetrate the no-metallic walls, and then, analyzing the received echo signal. However, the technology faces many challenges due to the presence of the wall, such as:1) Traditional transceiver, namely, SISO radar, using cross section observed manner, which result in the poor of the real-time imaging and anti-interference performance;2) Target weak reflection is submerged by the strong reflection of wall;3) Larger errors in wall parameters cause smearing of the image and displace target away from their true positions;4) Traditional wall compensation imaging methods have defect of a high computation complexity, which take inconvenience to real-time imaging;5) The detection from a single view could not image the targets which occluded by other target or obstacle.In summary, an integrated research framework is present in this paper to solve the above challenges. The main study works are as follows:1. Radar signal preprocessing:Firstly, according to FDTD principle to perform the forward modeling simulation on two-dimensional through-the-wall model, by which the receiving data of the pulse and multi-input and out-put radar system is gotten, namely the forward data profile. Secondly, in signal domain, two signal preprocessing methods for the information of radar reflection signal energy are proposed; in spatial domain, the other two echo pretreatment methods for the characteristic information of radar echo signal are presented. Finally, making contrast to these four methods for separating target reflection and clutter (direct wave and wall reflection).2. Wall parameters estimation:According to the reflection signal amplitude and time-delay from the front and back side of the wall, three estimation algorithms are proposed to accurately predict wall parameters, which including permittivity and thickness.3. Imaging method:Analyzing the traveling distance of electromagnetic wave as it travels from the transmitter to the target, and back to the receiver, then, a fast wall compensation algorithm is presented to single-view imaging. Finally, under the conditions of multi-view detection, all imaging results of different view will be integrated by the fusion algorithm, and then the target which hidden by other target or obstacle will be clearly imaging.