The Research On Virtual Multi-views Through-the-wall Radar Imaging

Through-The-Wall Radar(TWR) objects imaging is the crucial step of complex environment sensing and understanding which has been widely applied in military,enforcement and civilian tasks, because the Ultra-wideband(UWB) radar has great capabilities in high range resolution, strong penetration capabilities, and strong anti-jamming ability. Due to the existence of targets inside a room or in an enclosed structure, the receiving antenna will receive the multipath components apart from the target signals, such as the signals originating from the interaction between the targets and walls, which results in false targets or ghosts in the imaged radar imagery and poor signal-to-clutter ratio(SCR). In the traditional processing of through-wall radar scattered data, the multipath return was regarded as clutter and many methods was proposed to suppressing these interference. Multipath provides additional views of the targets, which can be exploited to improve the performance of the through-wall radar system. The time-domain ultra-short impulse ultra-wideband TWR has the ability of decorrelating multipath returns, understands thoroughly the mechanism of multipath returns including different views of the same object, researches virtual multiple-views imaging method based on radio propagation model.Firstly, Back Projection imaging algorithm is used to realize the targets imaging inside indoor structure. Through the analysis of the multipath scattering model and the rapid wall compensation algorithm in consideration of the multipath component,realize the target fast single perspective imaging. As the existence of multipath return,the imaged radar imagery has ghosts.Secondly, researches are working on how to identify the target and ghosts location. For a given parameter information of the indoor scene, the locations of the ghosts are relatively fixed in the image. By selecting two different antenna locations as the center of the circular contours, two circular contours method is used to identify the ghosts location.Lastly, on the basis of locating the multipath ghosts, this paper uses indoor radio propagation revised model and multiple-path scattering model, researches the designof mapping matrix and mapping strategy by using the Gaussian-weighting function,revised Green function, exponential weighting function. The main advantages of such an association or mapping are reduction in false positives in the original beamformed image and an increase in the SCR at the target coordinates, and the decoupling of the interaction between the targets and walls is achieved.