| 摘要 |
<P>PROBLEM TO BE SOLVED: To achieve downsizing and weight saving, enable a true azimuth to be measured even in an iron casing pipe, and allow reliability to be improved, cost to be reduced, and measurement time to be shortened. <P>SOLUTION: A pair of MEMS type gyro sensors 10 are mounted on both front and rear surfaces of a print circuit board 12, respectively, such that input axes thereof are opposite to each other to form a gyro unit 14, and a number of the gyro units are disposed in the circumferential direction to configure a sensor assembly 16. For each gyro unit, subtraction processing is performed on sensor output having an inverse phase each other from both MEMS type gyro sensors paired with each other to obtain an angular velocity signal. For example, the gyro units are structurally disposed at equal intervals in the circumferential direction so as to be laid across two regular-polygon-shaped gyro unit anchor blocks installed at an interval in the center axis direction. Angular velocity data obtained from each gyro unit is used as a sinusoidal wave of one wavelength and a phase is obtained by a least square method to calculate a true north. <P>COPYRIGHT: (C)2013,JPO&INPIT |
