Through-wall Radar Research Articles

A Compact UWB Indoor and Through-Wall Radar with Precise Ranging and Tracking

Ultrawideband (UWB) technology has many advantages compared to its narrowband counterpart in many applications. We present a new compact low-cost UWB radar for indoor and through-wall scenario. The focus of the paper is on the development of the signal processing algorithms for ranging and tracking, taking into account the particular properties of the UWB CMOS transceiver and the radiation characteristics of the antennas. Theoretical analysis for the algorithms and their evaluations by measurements are presented in the paper. The ranging resolution of this UWB radar has achieved 1-2 mm RMS accuracy for a moving target in indoor environment over a short range, and Kalman tracking algorithm functions well for the through-wall detection.

Removing Direct Wave of Through-Wall Radar Based on Singular Value Decomposition

The problem of target detection which is affected by the direct wave is discussed in this paper. Singular Value Decomposition method is proposed for removing the direct wave. The echo signal is decomposed by use of Singular Value Decomposition method and the one-order eigenvalue of the eigenvalue matrix is set to zero, then the related components of echo signal are removed. The direct wave signal can be removed effectively using this method, and most of the target components of signal are preserved in the process of removing direct wave signal. HFSS simulation software is used for modeling and simulation, and the results show that the resolution of false target using Singular Value Decomposition method increases 11% compared with the Interference Canceling method for removing direct wave.

Target Localization and Identification Algorithm for Ultra Wideband Through-wall Radar

穿墙目标探测是超宽带脉冲雷达在反恐斗争、灾难救援、城市巷战等方面的一个重要应用。SEABED算法是基于超宽带脉冲雷达的一种新型目标定位识别算法，但其不适用于对障碍物背后的目标进行定位的情况。该文在SEABED算法的基础上，分析SEABED算法在穿墙探测中的不足，提出一种新的定位算法使得SEABED算法能够对目标进行定位识别。该算法假设在近场条件下，利用回波时延差的关系曲线求得入射角，从而结合几何关系消除墙体对传播时延和传播路径的影响，将SEABED算法应用于穿墙成像应用中。仿真结果表明，该算法能够弥补墙体对SEABED算法的影响，精确度高，目标定位识别效果好，达到穿墙探测的目的。

Investigation of Circular Pipes as a Propagation Channel for Through-Wall Radar

The potential of using a circular metal pipe with two open ends as a propagation channel for through-wall radar is investigated. A modal formulation is used for simulating the backscattering from a target through a circular pipe. A target is observed through the pipe using simulation and subsequently validated with measured data. The insertion loss due to the pipe is extracted from simulation and compared to previously published data for the insertion loss of walls.

IMPROVEMENTS IN A HIGH GAIN UWB ANTENNA WITH CORRUGATED EDGES

In this paper, a novel corrugated structure at the edges of the Vivaldi substrate is presented. Compared with the Vivaldi antenna without corrugated structure, the new structure has a better radiation pattern. While compared with the traditional corrugated structure, the new structure has a better front-to-back ratio (F/B ratio). Properly chosen thickness and dielectric constant of substrate ensure a relatively small size while the lower frequency is around 1GHz. A Vivaldi structure also promises high gain in ultra-wideband (UWB) range. For its planar structure, the antenna is easily fabricated with a low cost. The design of a novel Vivaldi antenna described in this paper operates from 1GHz to more than 3GHz with i10dB return loss and produce the gain with a range of 7dBi » 11dBi. The current design is one of the most ideal antennas to be used for through-wall radar.

APPLICATION OF TRM IN THE UWB THROUGH WALL RADAR

Time Reversal Mirror (TRM) technique, in the virtue of its high resolution in the heterogeneous media, has been widely applied in the area of acoustics and electromagnetics. In this paper, the technique is developed to imaging targets in the contest of ultra-wideband (UWB) through wall radar (TWR) through numerical simulation. We firstly consider the technique to image targets behind a single-layered wall and then extend to the multi-layered wall. The simulation results have reported the imaging capability of the algorithm and its powerful use for TWRimaging. For concerning the image stability, we investigate the TRM images for the case in which there is a mismatch between the walls associated with the forward and inverse phases of time reversal. The back projection imaging algorithm is compared here at the same time for a contrast of the imaging quality. Finally, some conclusions are drawn.