Single point offset calibration for inertial sensors

摘要

A hand-held processor system for processing data from an integrated MEMS (Micro-Electro-Mechanical-Systems) device disposed within a hand-held computer system and methods therefor. The Single Point Offset Correction (SPOC) process computes offset values to calibrate MEMS sensors using a single set of data measurements at an orientation without dynamic perturbation, and without requiring advance knowledge of orientation of the device. Arbitrary output biases, which are known to be dominant on a single axis, can be corrected to ensure consistent performance. The SPOC process provides a simple method to effectively calibrate a MEMS sensor without requiring extensive system resources. This process can be enhanced by additional estimations of sensor offsets using the set of data measurements or by use of rule-based empirical gain factors.

主权项

1. A micro-processor, on-chip logic, or software implemented method for processing data from a MEMS (Micro-Electro-Mechanical-Systems) sensor disposed within a hand-held computer system programmed to perform the method, the method comprising:
determining, by a user of the hand-held computer system, that the z-axis offset of the hand-held computer system is worse than the offsets in the x-axis and y-axis; maintaining, by the user, the hand-held computer system in static position without dynamic perturbation; sensing, by the MEMS sensor disposed within the computer system, a single calibration data measurement point by sensing a set of X, Y, and Z axis sensor data in one static orientation for a predetermined time period, wherein the X, Y, and Z axis sensor data are denoted as Xm, Ym, and Zm, respectively; and determining, with a processor disposed within the computer system, computed offset data for the MEMS sensor through a Single Point Offset Correction (SPOC) process using the single calibration data measurement point, wherein the SPOC process comprises determining an offset value of the computed offset data via the following equation:
Offset Dependent Error=1g2−(Xm2+Ym2+Zm2), where g=9.8m/s2; performing measurement using the MEMS sensor; and applying the Offset Dependent Error to z-axis measurement data for offset correction.