Method and apparatus of interrogating a volume of material beneath the ground including an airborne vehicle with a detector being synchronized with a generator in a ground loop

摘要

PCT No. PCT/AU92/00166 Sec. 371 Date Oct. 29, 1993 Sec. 102(e) Date Oct. 29, 1993 PCT Filed Apr. 15, 1992 PCT Pub. No. WO92/19989 PCT Pub. Date Nov. 12, 1992A method of interrogating a volume of material beneath the ground. According to the method a transmitter is located to extend over and be supported by a surface area of ground encompassing and beneath which lies the volume of material. A generator device is used to generate transient electromagnetic pulses within the transmitter. An airborne vehicle, aboard which is a detector, is used to fly over the area of ground. The detector and the generator are synchronized to one another so that the detector has information regarding when the transient electromagnetic pulses are generated. The detector detects the resultant electromagnetic field of the transient electromagnetic pulses, which have certain magnitude and temporal characteristics. A received signal is formed by the detector, which signal is dependant upon the magnitude and the temporal characteristics of the detected electromagnetic fields. The received signal is thereafter processed to determine characteristics of the volume of material.