Measurement Non-Linearity
Operational performance parameter represents the numerical difference in sensor sensitivity between positive and negative directions of the measured physical quantity. The scale factor asymmetry governs the output deviation of inertial sensors subjected to alternating or bidirectional inputs. It ceases to apply if the input remains strictly unidirectional or does not cross the zero point.
Physical Sources
Structural and electronic asymmetries are the primary causes of this sensitivity imbalance. In silicon gyroscopes, scale factor asymmetry can arise from non-uniformities in the electrode gaps or from asymmetric gain in the analog front-end amplifiers. This results in the sensor responding differently to clockwise and counter-clockwise rotations.
Calibration Compensation
Correction algorithms must be applied in the digital signal processor. To minimize scale factor asymmetry, separate calibration coefficients are stored for positive and negative inputs, and the appropriate factor is applied based on the sign of the measured value. This correction is verified during thermal and mechanical stress testing.
System Integrity
Unchecked sensitivity imbalances can lead to cumulative errors in navigation algorithms. High scale factor asymmetry causes angular rate integration to drift over time during repetitive oscillatory motion, which can compromise the accuracy of positioning systems. Correcting this error is critical for tactical-grade applications.
