| 摘要 |
<p>Method and apparatus to determine the trace and depth of metallic conductors (6) located beneath ground level. The substance of the method is that ferrite antennas (16, 16") are matched to coupled parallel oscillating circuits the capacitive element of which provides resonance frequencies equal to the (cp +- 1)-th, preferably (cp-1)-th and cp - th, or (2c +- 1)-th, preferably (2c-1)-th and 2c-th upper harmonic of the basic frequency of the alternating current, where c is a properly selected integer higher than 1, the value of p is 1, 2, 3 or 6 as required, while cp is an even number, thereafter the trace of the conductor (6) is localized by detecting the vertical component (5) of the magnetic field at an upper/lower level and the horizontal component (4) at a lower/upper level, on the basis of the ratio of the two components the trace is approximated to a certain extent, then in order to measure the depth (4) of said conductor (6) the horizontal component (4) of the magnetic field is detected both at the upper and the lower level and the depth (4) is determined by the known formula. The apparatus comprises an upper and a lower ferrite antenna (16, 16") at least one of which can be rotated in the vertical plane. By means of the method and apparatus provided by the present invention the trace and depth of conductors conducting an alternating current can be determined with a high selectivity and accuracy. </p> |
