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Method and apparatus for compensating a magnetic compass

  • US 5,131,154 A
  • Filed: 10/15/1990
  • Issued: 07/21/1992
  • Est. Priority Date: 10/15/1990
  • Status: Expired due to Term
First Claim
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1. The method of compensating a magnetic compass in a vehicle for magnetic deviation of the earth'"'"'s magnetic field comprising the steps of:

  • (1) orienting the vehicle in any selected direction relative to magnetic north,(2) measuring the angle between a direction reference axis of the vehicle and the direction indicated by said magnetic compass in said vehicle,(3) adding a magnetic field at a known angle relative to said direction reference axis of the vehicle and memorizing the strength of the added magnetic field required to displace the direction indicated by said compass through a first predetermined angle,(4) and calculating the strength of the resultant magnetic field using the measured angle, the first predetermined angle and the memorized strength of the added magnetic field,(5) orienting the vehicle with said direction reference axis pointing one hundred eighty degrees away from said selected direction,(6) measuring the angle between the direction reference axis of the vehicle and the direction indicated by said magnetic compass,(7) adding a magnetic field at a known angle relative to said direction reference axis of the vehicle and memorizing the strength of the added magnetic field required to displace the direction indicated by said compass through a second predetermined angle,(8) calculating the strength of the resultant magnetic field using the last measured angle, the second predetermined angle and the last memorized strength of the added magnetic field,(9) and using the values of said resultant magnetic fields to determine the compensation required for said magnetic deviation.

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