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Method, system and device for calibrating a magnetic field sensor

  • US 7,119,533 B2
  • Filed: 04/20/2005
  • Issued: 10/10/2006
  • Est. Priority Date: 09/29/2004
  • Status: Active Grant
First Claim
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1. A control method of controlling a magnetic-field sensor for detecting the three-axis components of the terrestrial magnetic-field vector, said method comprising:

  • calculating a reference coordinate point in a predetermined coordinate space by performing coordinate transformation for the three-axis components of the terrestrial magnetic field vector as a reference, and holding said reference coordinate point thus calculated;

    acquiring the three-axis component outputs of said magnetic-field sensor occurring when said sensor assumes five or more attitudes;

    performing coordinate transformation for the three-axis components thus obtained for each attitude to calculate five or more coordinate points in the same coordinate space as with said reference coordinate point;

    selecting four points which are as far as possible from one another among the five or more coordinate points, creating a sphere on which said selected four coordinate points are positioned, and obtaining a magnetic-field offset by calculating the distance between the center of said sphere thus created and said reference coordinate point; and

    calibrating said magnetic-field sensor using said magnetic-field offset.

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