Determination of the sensitivity phase of an accelerometer based on an analysis of the harmonic components of the interference signal

Abstract

We propose a simple method to estimate phase lags of the sensitivity of an accelerometer via primary vibration calibration. The method adopts the same homodyne interferometer as used in other primary calibration methods, e. g. a sine-approximation method, but uses a different signal-processing scheme. Assuming that the accelerometer is under sinusoidal excitation, we have Fourier transformed the interference signal from the photodetector directly. The interference signal in the frequency domain can be expanded into a series of infinite harmonic components with orders of n ( n = -infinity,...0,..., +infinity), where each phase is an integer ( n) multiple of a principal phase. We have derived a technique to find the principal phase from several harmonic components using the least-squares method. Experimental results showed good agreement with those of other methods, thus verifying that the proposed approach is reasonable. Given its simplicity and efficiency, the proposed method has the potential to be adopted as an alternative method for estimation of the phase lag of the accelerometer.