Drift error analysis caused by RLG dither axis bending

In this paper, a drift error equation caused by the flexure of ring laser gyroscope (RLG) mechanical dither is derived for analyzing the effect on system performance in the presence of input acceleration. To separate the effects of dithering rate motion and vehicle rate motion, the flexure error is classified as sensor level error if the sensing axis coincides with the dithering axis and as system level error if the two axes do not coincide. The drift error is then derived by using the relationship between gyro output and the rotation vector. These equations show that RLG-based INS attitude error caused by the flexure is directly proportional to time, the amount of input acceleration and the dynamic frequency of the vehicle.