| 摘要 |
PCT No. PCT/SE80/00306 Sec. 371 Date Jul. 8, 1981 Sec. 102(e) Date Jul. 8, 1981 PCT Filed Nov. 28, 1980 PCT Pub. No. WO81/01617 PCT Pub. Date Jun. 11, 1981.The present invention relates to a method and apparatus for determining the electrical conductivity of the ground, particularly in connection with aerial prospecting, with the use of a transmitter unit (S) and a receiver unit (M) located at a distance from said transmitter unit and particularly carried by an aircraft (21). The transmitter is arranged to generate an electromagnetic field which induces an electric current in the ground, and the receiver is arranged to measure magnetic and electric fields induced by said current at the measuring site, said fields representing a measurement of said electrical conductivity and variations therein. The magnet field from the transmitter is transmitted horizontally as is directed transversally of an imaginary line that connects the transmitter (S) with the receiver (M). The electric field E from the transmitter is measured in the receiver in a radial direction to the transmitter. The magnetic field H is measured in a direction parallel with the magnetic transmitter-field. Of the measured magnitudes E and H the ratio E/H and/or the phase difference psi are formed, both of which are dependent on the electrical conductivity of the ground.
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