Rotational Error
Optical signal variations occurring within a fiber optic gyroscope interfere with the measurement of angular velocity. This non reciprocal phase drift results from environmental factors affecting the light beams. It represents the primary source of bias instability in high-precision navigation systems.
Thermal Sensitivity
Temperature changes across the coil diameter create different refractive index profiles for the clockwise and counterclockwise waves. When thermal sensitivity is active, the non reciprocal phase drift appears as a false rotation signal that changes as the heat propagates through the fiber layers. Symmetric winding patterns like the quadrupole configuration reduce this sensitivity by ensuring that equidistant points from the coil center experience the same thermal conditions.
Vibration Impact
Mechanical stress alters the optical path length of the fiber through the strain-optic effect. High-frequency oscillations can induce a non reciprocal phase drift if the stress is not perfectly uniform throughout the sensing loop. Shielding the sensor with damping materials and rigid enclosures helps maintain the stability of the phase relationship.
Calibration Requirement
Periodic testing against a known stationary reference allows for the characterization of the residual error. The magnitude of the non reciprocal phase drift is recorded over a range of operating temperatures to create a compensation table. This data is then used by the processing electronics to subtract the predicted drift from the live rotation measurement.
