| 摘要 |
PROBLEM TO BE SOLVED: To provide a method with which a disturbance magnetic field in an object position can be estimated from measurements of magnetic sensors in separated positions on the basis of a distance attenuation expression of an inverse power.SOLUTION: Magnetic sensors 20 are installed in a plurality of predetermined positions S away from an object position P exposed under a disturbance magnetic field B and while assuming a common gradient direction gof the disturbance magnetic field B in a space including the object position P and the sensor positions S, that gradient direction gis calculated from the positions S and measurements Bs of the sensors 20. A disturbance magnetic field Bp in the object position P is then estimated based on a distance attenuation expression A of the disturbance magnetic field B from a shading position R for which each sensor position S is vertically drooped on a straight line I in a calculated direction (g) passing the object position P and the sensor measurements Bs. Preferably, the magnetic sensors 20 are installed in three or more predetermined positions S1, S2, S3, the common unit gradient vector gof the disturbance magnetic field is assumed and the positions S1, S2, S3 of the sensors 20 and measurements B1, B2, B3 are substituted to a primary or high-order approximation of a Taylor expansion formula of the disturbance magnetic field B, thereby calculating the gradient vector g. |
