Real-time accelerometer calibration

A method for real-time accelerometer calibration on an electronic device, the method comprising:

• receiving, from the accelerometer, a plurality of acceleration measurements, wherein each acceleration measurement of the plurality of acceleration measurements represents an estimated acceleration vector, and wherein the estimated acceleration vector comprises a linear acceleration component and at least one error component that offsets the estimated acceleration vector from a true acceleration vector;
• selectively storing, in a data set, one or more of the plurality of acceleration measurements based on a result of a comparison of the linear acceleration component to a maximum threshold value;
• maintaining an accelerometer error correction model that includes calibration parameters for the at least one error of the estimated acceleration vector;
• determining calibration values for the calibration parameters using the accelerometer error correction model and the one or more of the plurality of acceleration measurements in the data set;
• and
• determining a calibration corrected estimate of a true acceleration vector that corresponds to a subsequently received acceleration measurement using the calibration values and the accelerometer error correction model.

A method for re-calibrating an accelerometer on an electronic device, the method comprising:

• generating a temperature measurement;
• receiving, from the accelerometer, a plurality of acceleration measurements, wherein each acceleration measurement of the plurality of acceleration measurements represents an estimated acceleration vector, and wherein the estimated acceleration vector comprises at least one error component that offsets the estimated acceleration vector from a true acceleration vector;
• maintaining an accelerometer error correction model that includes calibration parameters for the at least one error of the estimated acceleration vector;
• determining, based on the temperature measurement, that a recalibration condition has been met;
• determining, as part of a recalibration, calibration values for the calibration parameters using the accelerometer error correction model and the plurality of acceleration measurements;
• storing the temperature measurement and the calibration values for the calibration parameters in a data set;
• and
• determining a calibration corrected estimate of the true acceleration vector that corresponds to a subsequently received acceleration measurement using the calibration values and the accelerometer error correction model,
• and subsequently,
• determining, based on a subsequent temperature measurement, that the recalibration condition has been met;
• re-determining the calibration values for the calibration parameters based on the data set and the subsequent temperature measurement;
• and
• re-determining the calibration corrected estimate of the true acceleration vector that corresponds to an additional subsequently received acceleration measurement.