| 摘要 |
PURPOSE:To take an accurate azimuth measurement by engaging previously the engaging part of a gyro incorporated container with the engaged part of a holder for holding the gyro incorporated container which is set facing in a specific direction, and adjusting the zero point of a gyro. CONSTITUTION:A preliminary adjusting device D is installed at a specific position and a theodolite is used to set the NS azimuth of a scale plate 16 to the due north obtained through astronomical observation. Then, the holder 7 is rotated and one of indexes of an index ring 15 is set to a position N of the scale plate 16 so as to set the position of a key 14 to the due north. In this state, the scale plate 16 and holder 7 are fixed to a main body 3 in one body. Then, when the watertight container 11 incorporated with the gyro unit is inserted into the holder 7 through a bushing 13, a key groove engages with the key 14. |
