| This dissertation describes the use of random noise radar techniques to detect, localize and identify shallow buried subsurface objects, especially mines and mine-like targets. A novel polarimetric random noise Ground Penetration Radar (GPR) system has been designed, fabricated and tested at UNL. Stokes vector-based polarimetric techniques are applied for data processing. This dissertation presents a review of the existing GPR systems, their salient features and limitations, fundamentals of electromagnetic theory for GPR applications, the random noise radar technique and its theoretical considerations, and the system test results using random noise polarimetry.; This novel polarimetric random noise radar system transmits the wide bandwidth random noise signal in the 1-2 GHz frequency range. Detection and localization of buried objects is accomplished by correlating the reflected waveform with a time-delayed replica of the transmitted waveform. Broadband dual-polarized log-periodic antennas are used for transmission and reception. A unique signal processing scheme is used to inject coherence into the system by frequency translation of the ultra-wideband signal by a coherent 160 MHz phase-locked source prior to performing heterodyne correlation. System coherence allows the extraction of the polarimetric amplitude and phase characteristics of a target. The raw data images and Stokes matrix and polarimetric factor images are presented to demonstrate results of the experimental study. |
