Quadrupolar Fiber Gyroscope Bias Drift Mitigation under Transient Thermal Gradients
Quadrupolar winding cancels symmetric thermal gradients, leaving elasto-optic drift manageable via compliant potting and multi-point sensor compensation.
Elasto-Optic Drift
Optical Interference
Mechanical stress induced by external pressure or thermal expansion alters the refractive index of a glass fibre through a specific physical mechanism. This phenomenon, known as elasto-optic drift, causes a shift in the phase of light propagating through the sensing medium. It occurs when the strain state of the material changes during operation.
Error Mechanism
Dimensional changes in the sensor housing apply parasitic forces to the optical core. These forces induce birefringence that complicates the signal processing and obscures the intended measurement. If the mounting hardware expands at a different rate than the glass, the resulting signal includes a component that does not relate to the rotation or acceleration being measured.
Drift Mitigation
Symmetrical winding techniques and specialized potting compounds reduce the sensitivity of the coil to these mechanical fluctuations. Selecting materials with matched coefficients of thermal expansion minimizes the stress transfer from the environment to the fibre. Because the effect is often non-linear, compensation algorithms must account for the specific geometry of the sensor.
High precision applications rely on active temperature control to stabilize the mechanical state of the assembly.
Performance Limit
Uncompensated stress remains a primary source of bias instability in high grade inertial sensors. Even a small residual force creates a measurable error that accumulates over time. This error defines the boundary of the sensor performance during rapid temperature changes.