| 摘要 |
<p>PURPOSE:To decrease the number of receiving coils, and to measure the propulsion azimuth of a propeller even in a type, in which the receiving coils are fixed and measurement is conducted. CONSTITUTION:A magnetic field generated from a propeller 4 propelled under a ground surface is received by a receiving coil 1 on the ground, and a propulsion azimuth theta formed by the direction of the propeller 4 and a propulsion projected line 3 is obtained from theta=cos<-1> (V(alpha0/V--alpha (where alpha: an angle formed by the coil axis 2 of the receiving coil 1 and the propulsion projected line 3, V(alpha): voltage generated from the magnetic field in the receiving coil 1 when the angle formed by the coil axis 2 of the receiving coil 1 and the propulsion projected line 3 is alpha, V: voltage generated by said magnetic field in the receiving coil 1 when the angle formed by the coil axis 2 of the receiving coil 1 and the propulsion projected line 3 is 0).</p> |
