Patent ID: 7587277
Filing Date: 2009-09-08
Classification: G01C

Abstract:
1. One or more computer-readable media adapted for use with a computing device which is adapted to execute at least one of direction and motion measurement, said media having computer-usable instructions embodied thereon for performing a method comprising: computing body-sensed navigational frame magnetic field vector using sensed magnetic data; calculating attitude residuals between a group of body-sensed navigational frame magnetic field components and an initial magnetic reference frame; outputting said residuals to a Kalman filter process; measuring the observability for an attitude axis for each of roll, pitch, and yaw; producing a measurement-noise covariance matrix; using said measurement-noise covariance matrix in said Kalman filter process; detecting for motion; generating said initial magnetic reference frame if no motion is detected; taking running averages for magnetic field until a predetermined amount of time has elapsed; and outputting said running averages to serve as said initial magnetic field reference frame in said calculating step.