| 摘要 |
PURPOSE:To attempt improvement of detecting accuracy in the depth direction by in detection of position of a propulsor from the ground level, installing on the under-ground propulsor oscillator and oscillating coil. CONSTITUTION:An oscillating coil with a frequency capable of transmission of electromagnetic field even in the under-ground position is installed. Namely, in order to increase oscillating efficiency with oscillator 3 and oscillating oil installed on a propulsor, a value of Q is raised by installing in series a resonance condenser C in the oscillating coil 4. Further, in order to increase lateral detecting accuracy by using the symmetricity of the electromagnetic field, two detecting coils 5a, 5b are used and consequently side-swaying can easily be detected. A depth-direction detecting coil 6 is arranged at the center of the coils 5a and 5b and by making the point as the lateral zero-point and bringing the detecting coil 6 right above the propulsor a detected voltage of the coil 6 can indicate strength of the electromagnetic field in the depth direction and informations can be obtained from the detected voltage. |
