Patent ID: 9046343
Filing Date: 2015-06-02
Classification: E21B,G01B,G01C

Abstract:
1. A system comprising: one and only one three-axis magnetometer at a fixed location configured to determine a set of measurements taken from one observation point over a period of time of a time-dependent magnetic field caused by one and only one magnetic source rotating about an axis in a constant position during the period of time of measurement, wherein the set of measurements includes one axial component aligned with the axis and two transverse components transverse to the axis; and data processing circuitry configured to determine a transverse angle of rotation of the set of measurements, such that one of the two transverse components is ±π/2 radians out-of-phase with the other of the two transverse components when the measurements are transformed by the transverse angle of rotation, and to determine a spatial relationship between the magnetic source and the three-axis magnetometer based at least in part on the transverse angle of rotation.