Time-switched frequency modulated accelerometer long-term stabilization

Abstract

A method for improving long-term stability in a time-switched frequency modulated accelerometer includes demodulating a frequency of the time-switched frequency modulated accelerometer in an anti-phase vibrational mode one or more instances. Assuming an initial phase offset value, demodulating occurs in-phase and out-of-phase with a modulation reference to extract the in-phase and out-of-phase responses. The method further includes calculating a slope between the in-phase and the out-of-phase responses where if the slope is not equal to 1 or −1, the phase offset value is adjusted, and the demodulating is repeated until the slope is equal to 1 or −1. If the slope is equal to 1 or −1, the selected phase offset value is kept as a selected phase offset value. The method further includes using a linear model to detect bias drift with the out-of-phase response, thereby compensating for bias drift in the in-phase response.