Vehicle compass with automatic continuous calibration

  • US 4,953,305 A
  • Filed: 05/27/1987
  • Issued: 09/04/1990
  • Est. Priority Date: 05/27/1987
  • Status: Expired due to Term
First Claim
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1. In an electronic compass system for use in a vehicle such as an automobile comprising:

  • sensing means for detecting the earth'"'"'s magnetic field and for providing electrical signals representative of the direction of movement of the vehicle with respect to the earth'"'"'s magnetic field;

    circuit means coupled to said sensing means for providing display output signals representing heading information corresponding to the detected direction;

    display means coupled to said circuit means for displaying the vehicle heading in response to said display output signals, wherein the improvement comprises;

    said circuit means including means responsive to the direction representative signals for detecting the rate of change of said direction representative signals, and for determining if the rate of change exceeds a predetermined level thereby indicating the existence of invalid detected direction information; and

    means for providing an error output signal for display in response to said determining means determining that said rate of change exceeds said predetermined level.

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