| 摘要 |
<p>A radar-type underground prospecting apparatus detects the presence and position of a material such as gas conduit buried under the ground without the need of excavation. For this purpose, pulse waves having a constant peak value are periodically radiated froma pulse generator (4) into ground (5) through the ground surface (1). The waves reflected by the materials (8A, 8B) buried under the ground are trapped at the ground surface (1). The reflected waves corresponding to the pulse waves are amplified through a high-frequency amplifier (9) at an amplification degree that increases for each pulse radiation, and the outputs of the high-frequency amplifier (9) are sampled (11) at moments that are successively delayed each by a predetermined period of time on the basis of the individual radiation timings of pulse waves, thereby obtaining low-frequency signals whose time axes of pulse waves are extended. Waveforms of the low-frequency signals are displayed on a waveform display unit (12). Presence or absence of materials (8A, 8B) buried under the ground is detected on the screen of the waveform display unit (12) relying upon the presence of peaks in the low-frequency signals reflected by the materials (8A, 8B) buried under the ground, and the depth of the materials (8A, 8B) buried under the ground is detected depending upon the timings at which the peaks appear. The apparatus makes it possible to compensate attenuation of electromagnetic waves in the ground without causing distortion in the waveform.</p> |
