Coded pulse signal subsurface radar

Subsurface radar to detect buried objects from the ground surface by using electromagnetic waves has been used widely for detection of buried pipes si nce a shallow subsurface zone of up to 2 to 3 m can be visualized with high resolution at high speed. On the other hand, deeper subsurface detection i s required in searching for archaeological ruins. In this paper, a delay co rrelation-type subsurface radar using monocycle pulse signals modulated by M-sequence codes is proposed with a view to expanding the search range by i ncreasing the average energy of the transmitted signals. With a test setup, a steel pipe buried 2.5 m below the ground surface was detected with a tra nsmitting power of 1 mW. In regard to the maximum detectable range of the s ubsurface radar using this type of coded signals, this paper carries out a study from the point of view of both the time side-lobe and SIN. (C) 2001 S cripta Technica.