Patent ID: 8032324
Filing Date: 2011-10-04
Classification: G01C

Abstract:
1. A method for a device to estimate orientation comprising the steps; moving the device through a changing orientation in a sequence of time from an initial orientation to a final orientation; measuring a magnetic field in at least two axes of the device in timed sequence; and computing a transformation matrix, T, at each timed sequence as a product of rotations about the at least two axes of the device such that T=Π_i (Rp_i(ap_i)) wherein T is approximately determined as a combination of rotations about the at least two axes of the device such that the final orientation is estimated as the initial orientation of the device times the product of rotations, T, from the initial orientation to the final orientation and Rp_i(ap_i) is a rotation matrix for a rotation around axis Ui by angle ai wherein the device is operable to do the estimating, measuring and computing based upon the changing orientation of the device in timed sequence in the magnetic field.