Effective approach for actually uncorrelated angular vibration pattern design of a ring laser angle sensor

For small ring laser angle sensors that have several tens of centimeters of laser cavity perimeter, the laser cavities must be vibrated using uncorrelated white angular vibration in order to overcome the dead band. However, due to the high Q-factor structure of the angular vibrator, the realized frequencies and amplitudes of the angular vibrations do not change simultaneously corresponding to the input electrical signals. Therefore, uncorrelated white angular vibrations must be designed considering the actual responses of the angular vibrators. Thus, the actually realized angular vibration patterns corresponding to several types of electrical sequence signals were generated and stored. Next, using the modeling of a ring laser angle sensor and applying the stored actual angular vibration patterns, the simulation outputs of a ring laser angle sensor were generated and analyzed using the Allan variance. The results demonstrated that the imperfection of the angular vibration produced a rate random walk as well as a bias fluctuation. Based on these results and as a method for the realizing an uncorrelated angular vibration pattern design that considers the response of the angular vibrator, a simulation method for the design using experimentally stored angular vibration patterns is proposed. Also, in order to obtain a suitable pattern amplitude, the minimum flicker rate errors were investigated through variations in the pattern amplitude of the stored actual angular vibration patterns. These results were confirmed experimentally.