Pat.#5673050:		Three-dimensional underground imaging radar system
INVENTORS:		Moussally; George, Fremont, CA 94555-1117
		Ziernicki; Robert, Los Altos, CA 94022
		Fialer; Philip A., Palo Alto, CA 94303
		Heinzman; Fred Judson, Los Altos, CA 94024
ASSIGNEES:		none
ISSUED:		Sep. 30, 1997
FILED:		June 14, 1996
ABSTRACT: An ultra-wide band ground penetrating radar (GPR) system providing non-invasive detection and three-dimensional mapping of underground objects and voids. The performance of this radar provides improved underground object detection, location and identification over existing radars through the use of a novel interrupted, frequency modulated, continuous wave (FMCW) signal waveform. A synthetic aperture radar (SAR) technique known as spotlight mode focused (SAR) operation is used to collect data for the underground area of interest, by circumscribing this area with a radar beam provided on an airborne or ground based vehicle. Near-Brewster angle illumination of the ground is used to reduce losses.