DYNAMIC BIAS COMPENSATION FOR MEMS MOTION SENSORS

MEMS sensors output data that may be susceptible to systematic bias that diminishes the accuracy of the data. This disclosure is directed to a method that compensates for this bias so that the output is more accurate and representative. Once a movement of the proof mass of the MEMS sensor outputs a specific characteristic signal, and that signal is identified, the signal is dynamically processed to eliminate and/or reduce the offset. Some applications may require fast settling times, high accuracy of offset removal, and robustness to vibrations and shocks. These requirements typically conflict with each other, meaning that the faster the offset removal, the lower its accuracy, and the sensor is more susceptible to errors due to vibration and shock. In order to tradeoff these requirements, the output of the MEMS sensor is filtered with some non-linear and/or time variant processing, followed by averaging the signal during a startup phase over a steadily increasing number of sampling periods. Once the startup phase is complete, the offset compensation signal is determined and removed from the initial output signal from the MEMS sensor. By utilizing the disclosed method, it is possible to maintain a high accuracy of offset estimation, a fast settling time, while also mitigating the effects of external perturbations (e.g., shocks, vibrations) on the system during the offset estimation process.