Systems and Methods for Compensating for a Misalignment Angle Between an Accelerometer and a Magnetometer

摘要

A method for compensating for a misalignment angle between an accelerometer and a magnetometer includes applying a corrective rotation to collected accelerometer data or magnetometer data based on an estimated misalignment angle between an axis of the accelerometer and an axis of the magnetometer. The method further includes estimating a gravity vector using the corrected accelerometer data and estimating a magnetic field vector using the corrected magnetometer data. Additionally, the method includes calculating a characteristic that is a function of a calculated angle between the estimated gravity vector and the estimated magnetic field. The method also includes calculating a figure of merit over the plurality of times that is a function of the characteristic, and dynamically adjusting the estimated misalignment angle during ordinary use of the electronic device such that the figure of merit converges to a value as the electronic device rotates.

主权项

1. A method for compensating for a misalignment angle between an accelerometer and a magnetometer, comprising:
receiving accelerometer data from an accelerometer at a plurality of times; receiving magnetometer data from a magnetometer at a plurality of times; applying a corrective rotation to at least one of the accelerometer data and the magnetometer data based on an estimated misalignment angle at the plurality of times, the estimated misalignment angle being an estimate of an actual misalignment angle between an axis of the accelerometer and an axis of the magnetometer; estimating a gravity vector using the accelerometer data at the plurality of times; estimating a magnetic field vector using the magnetometer data at the plurality of times; calculating a characteristic that is a function of a calculated angle between the estimated gravity vector and the estimated magnetic field at each of the plurality of times; calculating a figure of merit over the plurality of times that is a function of the characteristic; and dynamically adjusting the estimated misalignment angle during use of the electronic device such that the figure of merit converges to a value as the electronic device moves with a non-zero rotation component that is orthogonal to a direction of gravity, wherein convergence of the figure of merit to the value indicates the estimated misalignment alignment angle is substantially equal to the actual misalignment error.