Degradation Modeling and Reliability Assessment of Fiber Optic Gyroscopes Based on Accelerated Degradation Test Data

Fiber optic gyroscopes (FOGs), as key components of inertial navigation systems, have largely replaced mechanical gyroscopes due to their high sensitivity and long service life. Accurate reliability assessment of FOGs is essential, yet direct lifetime data are scarce, limiting the use of conventional prediction methods. This study proposes a degradation-based modeling approach for reliability assessment of FOGs. Based on engineering knowledge, key performance indicators and primary accelerated stress factors-mainly temperature-are identified. The general path model and Wiener process models are constructed as candidates and validated with simulation data. Accelerated degradation test data from FOGs are used for deterioration modeling. Model parameters are estimated using maximum likelihood estimation, and the coefficient of determination (R²) is used to evaluate the model's goodness of fit. Results indicate that the general path model better captures FOG degradation. Reliability curves are derived, and the predicted lifetimes of both batches are obtained.