ROBUST FADING KALMAN FILTER BASED NONLINEAR ERROR REDUCTION IN A LASER INTERFEROMETER

摘要

In this paper, we propose a robust fading Kalman filter (RFKF) for improving the measurement accuracy of a heterodyne laser interferometer. The nonlinearity of a heterodyne laser interferometer is expressed as a state equation including the parameter uncertainty. We also consider the distorted signal of laser affected by Doppler effect and process noise. The RFKF overcomes the parameter uncertainty and the error covariance is estimated more precisely by using a fading factor. The RFKF compensation algorithm can improve the displacement accuracy since the fading factor adjusts the error covariance. The effectiveness of RFKF algorithm has been proved through the simulation and experiments.