Calibration and optimal compensation for size effect parameters of laser gyro SINS

An approach is derived to calibrate and compensate the size effect of SINS. At first, the level-arm parameters of the each accelerometer in a SINS relative to the rotation center of a three-axes turntable are calibrated. Then the size effect parameters relative to the optimal origin of the SINS body frame are obtained for minimizing size effect errors. The calibration repeatability of level-arm and size effect parameters is less than 0.2 mm for the accelerometer whose bias stability is better than 2 × 10?5 g. In order to validate the calibration and compensate the results using the gravitational acceleration, the rotation center of the three-axes turntable is selected as the origin of the body frame. It is showed that the average error in 10 min is less than 2 × 10 ?6gafter compensating when the turntable is rotating at a constant speed. The angular rate and the angular acceleration are computed from the angular increment samples of laser gyros and are used to compensate the size effect in the inertial navigation experiment. The position error of inertial navigation decreases to 300 m/h from 1600 m/h after size effect compensation under the condition that the turntable is in angular motion.