A New Method for Calibrating Nonlinear Coefficients of PIGA on Linear Vibrator

This paper proposes a method for calibrating nonlinear coefficients of pendulous integrating gyroaccelerometer (PIGA) on linear vibrator in order to increase the calibration accuracy. First, a series of coordinate systems is established by analyzing the working mechanism of linear vibrator, and the error sources during calibration process are described. The precise input-specific forces and angular rates of PIGA are derived by homogeneous transformation algorithm. Then, the calibration error model of PIGA is proposed, which jointly considers the second-order, the third-order, and the cross-quadratic terms. The parasitic rotation errors of linear vibrator are separated from error terms of the model by vibrating within integer periods, and the static errors are suppressed by subtracting the static test outputs. Finally, the frequency errors and the parasitic translation are estimated accurately, and the error model is simplified and compensated by the analysis of measurement. It is verified by simulations that the nonlinear coefficients of PIGA are identified accurately, and the magnitude of absolute errors are less than $10^{-6}$ . The simulation results also make contributions to the design of the test plan appropriately.