| US 7,587,277 B1 | ||
| Inertial/magnetic measurement device | ||
| Randy Wells, Huntsville, Ala. (US) | ||
| Assigned to Miltec Corporation, Huntsville, Ala. (US) | ||
| Filed on Nov. 21, 2005, as Appl. No. 11/285,644. | ||
| Int. Cl. G01C 21/00 (2006.01) | ||
| U.S. Cl. 701—220 | 25 Claims |
| 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.
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