Quadrature Compensation and Demodulation Phase Reference Selection for FM Accelerometers

This paper provides demonstration of a means to select the demodulation phase reference of time-switched frequency modulated (FM) accelerometers to utilize quadrature information to observe and correct for both short and long-term noise processes. While in theory time-switched FM accelerometers should be immune to slow drift processes such as temperature variations, temperature dependence has been observed in experimental implementations. This method builds upon prior results. As autoregressive modeling is no longer needed, this method can be used for nonstationary acceleration. Limited by the experimental setup, bias instability on the time scale of hours is improved by more than two orders of magnitude. As the bias instability was recorded at the longest possible integration time, future work plans to conduct trials to determine the ultimate limits of the proposed method.