| 摘要 |
PURPOSE:To provide reading of terrestrial magnetic azimuth with a small error despite a change in magnetic characteristics due to temperature fluctuation, by the specified arithmetic operations of outputs of detecting windings intersecting mutually through a right angle provided with center taps installed on magnetic exciting coils producing AC bias magnetic fields. CONSTITUTION:An AC bias magnetic field is produced by a magnetic exciting coil 2 of a troidal core 1. Around this core 1, X-, and Y-detecting windings 3, 4 intersecting at an approximately right angle are wound and differential voltages based upon the terrestrial magnetism corresponding to the existing azimuth are issued through each of ground connected center-taps 3a, 4a and windings 3, 4. These differential voltages are processed by synchronous wave detectors 7-10, integrators 12-15, switches 16, 17 and A/D convertors 20, 21, and integrating voltages of opposite polarities VX1 and VX2 and integral voltages VY1 and VY2 which are deviated in polarities from the formers by right angles respectively are supplied to a CPU 22. An azimuth (VX1-VX2)/(VY 1-VY2) of a small error basing on the terrestrial magnetism by subtraction and division free from effects of saturated magnetic flux density, magnetic permeability caused by temperature fluctuation is calculated.
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