Automatic calibration of magnetic compasses
CA 2133313 A1 · Owner: Her Majesty The Queen, In Right Of Canada, As Represented By The Ministe R Of Communications · Inventors: Dufour, Martial Joseph
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Automatic correction of hard-iron and soft-iron distortion in a magnetic compass is achieved by storing a set of measured magnetic field values for different discrete directions of the compass relative to an estimated origin. Values are interpolated for the directions not yet measured to provide a set of measured and interpolated values defining a substantially eliptical locus of the sensed magnetic field vector (ET). New coordinates for the estimated origin are derived and the measured values are adjusted to take account of changes in the estimated origin. The heading is corrected for displacement of the origin due to hard-iron effect and for ellipticity of the locus due to soft-iron …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed March 30, 1993. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended March 30, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 30, 2015.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.