A novel subsurface radar using a short chirp signal to expand the detection range

The use of a chirp signal is one of the methods to expand the detection ran ge in subsurface radar. However, the presence of time-sidelobes after a con ventional pulse-compression makes the detection range degraded because weak signals from underground objects are covered with a large time-sidelobe du e to a ground surface reflection. In this paper, we propose a new pulse com pression subsurface radar using a short chirp signal in which the echoes fr om the ground surface and the object are not overlapped. We show that the s hort chirp signal can improve the detection ability compared with a convent ional chirp signal and examine the influence that the decreases of the sign al duration and the compression ratio exert on the detection range. By the new pulse compression subsurface radar, the steel pipes buried down to 5 m in depth can be detected.