Vehicle compass system with continuous automatic calibration
US7458166B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 29, 2008 |
| Grant date | Dec 2, 2008 |
| Priority date | — |
| Expiry date | Jan 29, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01C17/38
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The compass system of the present invention utilizes an improved calibration route in which a processing circuit of the compass recalibrates the compass each time three data points are obtained from a magnetic field sensor that meet predetermined criteria. One such criterion is that the three data points define corners of a triangle that is substantially non-obtuse. When three data points have been obtained that define a triangle meeting this criterion, the processing circuit calculates a center point for a circle upon which all three data points lie by solving the equation x2+y2+Ax+By+C=0 for A, B, and C, using the coordinate values (x,y) for the three data points and defining the center point as (−A/2, −B/2).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.