Spherical calibration and reference alignment algorithms
US7930148B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 14, 2008 |
| Grant date | Apr 19, 2011 |
| Priority date | — |
| Expiry date | Aug 18, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01C25/005
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Inclinometer and directional field sensor readings can have gain, offset, and non-orthogonality errors, as well as reference alignment rotation errors. When a series of readings are taken by a three axis sensor with a variety of different orientations, the resulting dataset looks like a perfect hypothetical sphere in the absence of any errors; with errors as mentioned above the dataset looks like an offset, rotated, ellipsoidal quadratic surface. This invention provides a simple method of removing the above errors from a tilt reference device. A disclosed algorithm is divided into two distinct components: the ellipsoidal quadratic surface component, which covers gain, offset, and axis misalignment; and the rotation component, which covers rotation relative to a set of reference axes. The solution presented here addresses both components combined, or separated and for inclinometers, magnetometers and rate sensors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.