Bias Error
Rotational sensor error represents the slowly changing bias in angular rate measurements that occurs independently of actual physical rotation. In precision guidance systems, fiber optic gyro drift arises primarily from non-reciprocal phase shifts induced by environmental changes. This phenomenon causes an accumulated heading error that grows over time if left uncorrected.
Thermal Sensitivity
Asymmetrical temperature gradients across the fiber coil generate localized stress and modify the refractive index of the glass through the Shupe effect. These thermal variations produce a false rotation signal because counter-propagating light beams experience slightly different travel times through the fiber spool. High-performance instruments utilize quadrupole winding patterns to ensure that symmetric sections of the fiber experience identical thermal environments, reducing the magnitude of the error.
Calibration Method
Compensation algorithms run continuously on the sensor’s processor to subtract the predicted bias based on real-time temperature telemetry. Engineers characterize the sensor in specialized environmental chambers, measuring output at multiple stable points and during rapid temperature sweeps. This process generates a multidimensional look-up table that corrects the output for both static temperature and thermal rates of change.
Performance Limit
Modern fabrication techniques constrain the residual uncompensated error to fractions of a degree per hour.
