APPARATUS AND METHOD FOR THE ELIMINATION OF ANGULAR VIBRATION INDUCED ERRORS IN RING LASER GYROSCOPES

In a ring laser gyroscope which has a triangular block configuration, and which incorporates a triangular shaped laser resonant cavity defined by three corner mirrors, including an output mirror, the gyroscope is sinusoidally dithered to reduce lock-in effects at low angular rotational rates and the gyroscope output is corrected for error caused by lock-in at the extremities of each oscillation when the dither velocity is equal to zero by accumulating the ac voltage outputs of a photodiode measuring the light intensity of the interference pattern at each zero dither velocity and when the accumulated phase error reaches 2.pi. an overflow or borrow pulse is generated and added to the normal gyroscope output thereby correcting for the accumulated errors caused by lock-in at zero dither velocity.