| 摘要 |
PURPOSE:To acknowledge the timing when the recorrection of offset correction is to be performed appropriately, by monitoring the absolute value of the detected signal of a magnetic azimuth sensor after the correction, and detecting the variation of the absolute value depending on the azimuth. CONSTITUTION:The offset correction and the sensitivity correction of outputs X and Y detected by the magnetic azimuth sensor 1 are performed in a sensor output correcting part 6, and correction data X1 and Y1 are outputted. When the amount of magnetism contained in a body of a vehicle is changed, the offset state is changed, and the locus based on the correction data X1 and Y1 is shifted. Namely, difference is caused in the absolute value (X<1>2+Y<1>2)<1/2> outputted from an absolute value computing part 7, depending on the azimuths. The disagreement between the average value of the absolute values of the correction data and a reference value is detected, and the occurrence of the change in the offset state is warned. |
