Frequency Modulation
Rectification defines a signal conditioning process that removes unintended output bias from vibratory gyroscopes subjected to high-frequency vibrational input. Angular rate rectification occurs when the non-linear response of the sensing element produces a constant direct current offset in the presence of oscillating accelerations or angular rates. This phenomenon manifests as a rectified voltage or frequency shift that the signal processing chain misinterprets as a steady rotation.
Accurate inertial navigation requires isolation of these parasitic signals to ensure the sensor output maintains proportionality with the actual input rate.
Rectification Source
Mechanical asymmetries within the structural suspension of a micro-electro-mechanical system resonator permit the conversion of vibration into pseudo-rate signals. These asymmetries arise from manufacturing tolerances that prevent perfectly symmetric displacement under acceleration. Such imbalances trigger a shift in the resonant frequency or a change in the phase of the output signal as the device oscillates.
Designers mitigate this effect through laser trimming or electronic balancing circuits that minimize the coupling between linear acceleration and rotational sensing axes.
Compensation Method
Calibration engineers apply digital filters or hardware demodulation to identify and subtract the bias component derived from high-frequency vibrations. Periodic testing against known reference rates allows the characterization of the rectification slope for specific device architectures. Laboratory setups utilize shakers to subject the instrument to controlled vibrational noise while monitoring the zero-rate output for deviations.
Once the manufacturer quantifies the rectification coefficient under standard environmental conditions, software algorithms implement a dynamic correction factor that adjusts the output in real time.
Operational Limit
Tolerance constraints for this secondary output component dictate the maximum allowable vibrational environment for mission-critical deployments. Performance degrades when the amplitude of the environmental vibration exceeds the range over which the rectification model remains linear. Advanced sensor designs incorporate physical dampening structures to attenuate the energy reaching the sensing element before conversion occurs.
Failure to account for these rectified offsets results in long-term position integration errors that drift rapidly from the true coordinate.
