| 摘要 |
PURPOSE:To obtain a small-sized, inexpensive device which easily corrects deviation and a horizontal magnetic field with high accuracy by measuring plural reference directions and direction differences of the indicated azimuth of a terrestrial magnetic sensor from the azimuths, and calculating the sum of a geographic magnetic deviation value at a measurement point and its azimuth difference. CONSTITUTION:When deviation is corrected without considering geographic magnetic deviation, a deviation calculation contact is selected with a function switch 5 and a contact of, for example, the north is selected with an eight-azimuths selection switch 2. Then the bow of a ship is directed to the north on a map. At this time, a push button switch 6 is pressed to input the output of the terrestrial magnetic sensor 1 to the CPU of an arithmetic part 7, and the difference from a reference direction is calculated and stored in a memory. When the calculating operation is carried out for all eight azimuths, the arithmetic pat 7 generates a corrected value table of 0-360 deg. on the basis of deviation data. When the north pole is selected as are reference azi muth, a zero position contact is selected with the eight-azimuth selection switch 2, and the magnetic deviation value at the point is set by a geographic deviation value setter 3 and the push button is pressed. |
