Thermally induced bias error is one of the main performance limits for the fiber optic gyroscopes (FOGs). We reviewed the thermal sensitivity of FOG in detail and created a simulation environment by the Finite Element Method (FEM). Thermal sensitivity analysis is based on Shupe and elastooptic effects. Elastooptical interactions are modeled by using the two different FEM simulations and homogenization-dehomogenization processes. FEM simulations are validated by comparing the results with a laboratory FOG setup. We report the changes in the error characteristics for practical quadruple winding patterns.

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In this paper, we present the latest efforts of developing a navigation grade fiber optic gyroscope coil in Turkey. One of the main precision limits for a fiber optic gyroscope coil is its sensitivity to thermally induced rate error. We used an advanced thermal modeling of a fiber optic gyroscope coil in order to obtain the strain fields along the coil and calculate the rate error. An intermediate validation step which compares the strain field calculations with the optical time domain reflectometer (OTDR) measurements of a laboratory fiber optic gyroscope setup is presented. In literature, there are several works indicating the relation between strain and rate error and trying to reduce the total strain as a whole [1], [2]. The strain analysis is separated into axial and radial gradients along the fiber coil. A new fiber coil structure using titanium as the spool material is designed and two fiber coils are produced. Fiber coils are tested under a temperature profile ranging from-40 °C to +60 °C. Simulation and experimental results are consistent. Proposed coil design is promising with 8-fold reduction in rate error.

One of the performance limits of a navigation grade fiber optic gyroscope is the bias error due to the thermal sensitivity of the fiber coil. Thermal stress inside the fiber coil is an important source of the bias error. The reduction of the total stress inside the fiber coil can be limited. In this paper, it is shown that further improvement can be achieved by controlling the strain inhomogeneity through the fiber coil. A validated simulation environment is presented for strain distribution analysis. Thermally induced bias error formation mechanisms are compared. The effect of the strain inhomogeneity is reduced by presenting a different coil cross section and spool material. Experiments utilizing a coil design with better performance are presented for the verification of the approach.