06418376 is referenced by 158 patents.

An electronic compass system for use in an adjustable fixture in a vehicle such as an automobile including a sensor for detecting a magnetic field and for providing electrical signals representative of the direction of the vehicle with respect to the magnetic field. Relative position sensors provide electronic compass orientation relative to the vehicle. A circuit coupled to said sensing means resolve the direction and relative position electrical signals into a number of data points from which the detected direction of the vehicle may be calculated. The circuit also provides heading output signals representing heading information corresponding to the detected direction. An indicator coupled to the circuit provides an indication of the vehicle heading in response to said heading output signals, where the circuit includes a processor responsive to the direction electrical signals for determining a relative field strength of the magnetic field, for varying the resolution at which the circuit resolves the direction electrical signals into heading information as a function of the detected strength of the magnetic field, and for recalibrating the heading signal in response to sensor orientation signals to maintain accuracy of the indicated heading information. The processing means varies the resolution by adjusting the number of data points into which said direction representative electrical signals can be resolved.

Title
Method and apparatus to maintain compass heading with a moveable sensor mounting
Application Number
9/651521
Publication Number
6418376 (B1)
Application Date
August 30, 2000
Publication Date
July 9, 2002
Inventor
Thomas R Olson
Holland
MI, US
Agent
Foley & Lardner
US
Assignee
Johnson Controls Technology Company
MI, US
IPC
G08B 23/00
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