Modeling GPR echoes from land mines using linear combinations of exponentially damped sinusoids

Ultra-wideband returns from surface-scattered and buried land mines give distinctive echoes that depend on the target type and soil environment. These echoes remain relatively stable for land mines with non-metallic casings but vary with the soil environment for land mines with metallic casings. This fact indicates that the signature resulting from the non-metallic-cased land mine is due to internal structure, whereas the signature of the metallic-cased target is due to interaction of the illuminating pulse with the metal case and the surrounding medium. The shape of these echoes can be described by a series of damped sinusoids. Certain parameters of the functions are believed to be stable for the same target in a variety of environments. Thus the echo can theoretically be used to identify targets with non-metallic casings by determining the position of the fixed poles that describe the exponential dampled sinusoids associated with a particular target type. This paper examines extraction of these poles, by the Prony method, for different types of non-metallic land mines and land-mine-like targets.