Robert B Mcghee

US Patent:

6820025, Nov 16, 2004

Filed:

Oct 30, 2001

Appl. No.:

10/020719

Inventors:

Eric R. Bachmann - Oxford OH
Robert B. McGhee - Carmel CA
Xiaoping Yun - Salinas CA
Michael J. Zyda - Carmel CA
Douglas L. McKinney - Prunedale CA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G01C 1738

US Classification:

702 94, 600595

Abstract:

One embodiment the invention comprises a method of determining an orientation of a sensor. The method includes measuring a local magnetic field vector and a local gravity vector and using those measurements to determine the orientation of the sensor. Embodiments can include measuring the magnetic field vector and the local gravity vector using quaternion coordinates. Another embodiment comprises measuring a local magnetic field vector, a local gravity vector, and the angular velocity of the sensor. These three vectors are processed to determine the orientation of the sensor. In one embodiment the three vectors can all be measured in quaternion coordinates. Another method embodiment comprises determining a local gravity vector by providing a acceleration detector, moving the detector from a start point to an end point over a time period, and summing acceleration measurements over the time period. The local gravity vector is calculated using the summed acceleration measurements. A system embodiment of the present invention includes a body having mounted thereon at least one sensor.

US Patent:

7089148, Aug 8, 2006

Filed:

Sep 30, 2004

Appl. No.:

10/963007

Inventors:

Eric R. Bachmann - Oxford OH, US
Robert B. McGhee - Carmel CA, US
Xiaoping Yun - Salinas CA, US
Michael J. Zyda - Carmel CA, US
Douglas L. McKinney - Prunedale CA, US

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G01C 17/00
A61B 5/103

US Classification:

702151, 600595

Abstract:

One embodiment the invention includes a method of determining an orientation of a sensor. The method includes measuring a local magnetic field vector and a local gravity vector and using those measurements to determine the orientation of the sensor. Embodiments can include measuring the magnetic field vector and the local gravity vector using quaternion coordinates. Another embodiment includes measuring a local magnetic field vector, a local gravity vector, and the angular velocity of the sensor. These three vectors are processed to determine the orientation of the sensor. In one embodiment the three vectors can all be measured in quaternion coordinates. Another method embodiment includes determining a local gravity vector by providing a acceleration detector, moving the detector from a start point to an end point over a time period, and summing acceleration measurements over the time period. The local gravity vector is calculated using the summed acceleration measurements.