A novel coherent ultra-wideband radar system operating in the 1-to 2-GHz frequency range has been developed recently at the University of Nebraska. The radar system transmits white Gaussian noise. 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 ultrawideband signal by a coherent 160-MHz phase-locked source prior to performing heterodyne correlation. The system coherence allows the extraction of a target's polarimetric amplitude and phase characteristics. This paper describes the unique design features of the radar system, develops the theoretical foundations of noise polarimetry, provides experimental evidence of the polarimetric and resolution capabilities of the system, and demonstrates results obtained in subsurface probing applications.

A novel polarimetric ultra-wideband radar system operating in the 1-2 GHz frequency range for subsurface probing applications is currently under development at the University of Nebraska. The radar system transmits white Gaussian noise. 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 obtain the target's polarimetric amplitude and phase response by frequency translation of the ultra-wideband signal by a coherent 160 MHz phase-locked source. In addition, the radar system features high depth resolution, low bandwidth-duration product, as well as simplified signal processing. This paper describes the unique design features of the radar system, develops the theoretical foundations of noise polarimetry, and provides experimental evidence of the polarimetric and resolution capabilities of the system.

Random noise polarimetry is a new radar technique for high-resolution probing of subsurface objects and interfaces. Detection of buried targets is accomplished by cross-correlating the reflected signal by a time-delayed replica of the transmitted waveform. A unique signal processing scheme is used to inject coherence in the system to permit extraction of the wideband polarimetric scattering response of the buried object. This facilitates computation of the Stokes matrices of the target response which enhances the detection and identification process. Random noise polarimetry also possesses additional desirable features for subsurface probing such as immunity from detection and jamming. The paper discusses the theoretical foundations of random noise polarimetry and presents data acquired from various targets using a 1-2 GHz radar system fabricated by the University of Nebraska under contract to the U.S. Army Waterways Experiment Station. In addition, various signal processing algorithms used to analyze the polarimetric data are presented.

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