Study On Wideband Stepped Frequency Radar Through-the-wall Detection And Imaging

The through-wall radar, especially the broadband through-wall radar has beenwidely used in the fields such as earthquake rescue, anti-terrorism, security and so on,with the continuous expansion of application field and gradual growth of the marketscale, people not only hope through-wall radar continue to keep its excellentperformance of sensitive detection, accurate positioning, clear imaging, but also theybegin to demand the through-wall radar to be developed towards the practicalorientation of low-cost, high reliability. As a kind of a mature conventional radarsystem, stepped frequency radar has become the ideal solution for a through-wallradar to be developed towards practical orientation due to its advantages such assimple system structure, high reliability and low cost. In this paper, the author makesexploration and research on through-wall radar detection and imaging technology ofbroadband stepped frequency radar, and the author has achieved some progress inaspects such as the background interference cancellation, extraction of humandynamic features, positioning of human target.In this paper, the author uses vector network analyzer to generate steppedfrequency signal, and uses electric rail mobile transceiver antenna to form syntheticaperture, the vector network analyzer and antenna motion are controlled by labviewsoftware, so as to establish a simple and reliable stepped frequency through-wall radarexperiment platform. In addition, the author has used the above platform to do a largenumber of practical measured experiments and solved the key issues such as strongbackground interference, human features difficult to be extracted, imaging defocusingand so on through analysis and verification of the practical measured data. Accordingto the issue of over strong wall reflected signal existed in through-wall detection andimaging, the author proposes two kinds of cancellation method as both static anddynamic interference, the respective applicable scenes if above are analyzed throughexperiments. On the basis of cancellation, the author extracts the dynamic features ofhuman body targets such as running, walking, swinging limbs, breath as well asheartbeat and so on, the ranging detection and positioning of human body targets aredone based on the corresponding dynamic features. The author analyzes thepropagation features of electromagnetic wave in the wall of through-wall imaging,and the targets are imaged by using back projection (BP) approach to obtain a well focused imaging.