Calibration of 3d field sensors

Abstract

An apparatus-based method is disclosed for calibration of a 3D field sensor. The method comprises accessing a plurality of samples, where the samples are from the 3D field sensor. Each sample represents a magnitude and an orientation of a three-dimensional field sensed by the 3D field sensor. Using the plurality of samples, a plurality of parameters is determined of an ellipsoid. The determination of the plurality of parameters is performed so that the ellipsoid fits the plurality of samples. A transformation is determined that transforms the ellipsoid into a sphere. The transformation is applied to a sample to create a transformed sample. Apparatus and signal bearing media are also disclosed.

Description

Calibration of 3D field sensors technical field The present invention relates generally to sensors that measure three-dimensional (3D) fields, and more particularly to the calibration of such sensors. Background technique A 3D field sensor is a sensor that measures the direction and magnitude of a field in three-dimensional space. For example, a three-dimensional orthogonal magnetometer unit can measure the direction and magnitude of the surrounding magnetic field. Similarly, three orthogonal accelerometer units can sense acceleration or, more importantly, the direction and magnitude of a gravitational field that is usually indistinguishable from acceleration. As already suggested above, in almost all cases a 3D field sensor comprises at some level three one-dimensional sensors properly oriented relative to each other. The basic assumption in reconstructing the direction and magnitude of the measurement field is that the cells are orthogonal to each other and have simil...

AI Technical Summary

Problems solved by technology

This process still takes user input on known readings and is often difficult to implement with 3D field sensors

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