Patent ID: 9068832
Filing Date: 2015-06-30
Classification: G01C

Abstract:
1. A method for determining the direction of a magnetic field, the method comprising: measuring with a portable electronic compass device three field vectors of a magnetic field a desired number of times, forming from each measurement a data point in a three-dimensional co-ordinate system, calculating a common reference point for the measured data points, determining the location of the device relative to the reference point in the co-ordinate system, comparing the co-ordinates of the reference point obtained to the co-ordinates of at least one previous reference point, calibrating the co-ordinate values of the reference point, and indicating the direction of the magnetic field with the aid of the reference point, wherein the data points are formed on an essentially spherical surface and the calculated reference point is the centre point of the sphere, and wherein the reference point is calculated by forming three line segments between selected data points, from which unit vectors are formed for three planes passing through the centre points of the segments, the intersection point of the planes being the reference point.