Optical fiber gyroscope for automotive navigation

Comparative Assessment on the Performance of Open-Loop and Closed-Loop IFOGs

“…It works based on Sagnac shift effect and requires high vacuum and precision mirror technology, which makes this technique very expensive [4]. The physical principal of RLG operation is analogous to the Doppler Effect, but it involves determination of the phase shift between two counter-propagating light beams in an evacuated mirrored cavity [6]. To address this drawback, interferometric fiber optic gyro (IFOG) is employed whose function resembles RLG, notwithstanding the fact that, in IFOG, the same effect is obtained in a fiber coil with the elimination of the high voltage and high vacuum, which results in a low-cost inertial rotation sensor [4,6].…”

“…The physical principal of RLG operation is analogous to the Doppler Effect, but it involves determination of the phase shift between two counter-propagating light beams in an evacuated mirrored cavity [6]. To address this drawback, interferometric fiber optic gyro (IFOG) is employed whose function resembles RLG, notwithstanding the fact that, in IFOG, the same effect is obtained in a fiber coil with the elimination of the high voltage and high vacuum, which results in a low-cost inertial rotation sensor [4,6]. In addition, IFOGs are abstracted in miniature devices; all-solid state with a limited number of components, therefore lower cost.…”

“…Given the advantage of this effect, the actual path length difference due to the rotation is quite small, e.g. the gyro used in the aircraft navigation must detect rotation rates below 0.01 deg/hr [6]. FOG is used for measurement of the rotation based on Sagnact Effect.…”

“…Path length measurement in RLG is performed by measuring the difference of resonant frequencies between two cavities [5]. Despite, IFOG rotation rate sensing is achieved through a direct measurement (open loop) or nulling (close loop) of the optical phase difference due to the rotation-induced Sagnac phase shift [4,6,7].…”

Investigation on Closed-loop Fiber Optic Gyroscope Structure and Operation

“…It works based on Sagnac shift effect and requires high vacuum and precision mirror technology, which makes this technique very expensive [2]. The physical principal of RLG operation is analogous to the Doppler Effect, but it involves determination of the phase shift between two counterpropagating light beams in an evacuated mirrored cavity [3]. To address this drawback, interferometric fiber optic gyro (IFOG) is employed whose function resembles RLG,…”