Transient Thermal Calibration in Quartz Resonant Accelerometers
Transient thermal calibration compensates quartz resonant accelerometer bias shifts caused by temperature gradients using differential thermal rate models.
Quartz Resonant Accelerometer
Inertial Instrument
Precision sensors measure linear acceleration by tracking changes in the resonant frequency of quartz beams under load. This instrument, known as a quartz resonant accelerometer, converts the proof mass displacement into a frequency output that can be measured directly by digital circuits. It is used in high-precision navigation and guidance systems.
Force Conversion
Applied acceleration shifts the proof mass, which exerts a tensile or compressive force on the crystalline sensing element. In a quartz resonant accelerometer, this force modifies the stiffness of the vibrating beam, shifting its resonant frequency. This frequency shift is proportional to the applied acceleration, providing a highly linear and stable measurement.
Calibration Constant
Laboratory tests determine the scale factor and bias coefficients of the sensor across its operating range. These parameters of the quartz resonant accelerometer are loaded into the system computer to compensate for temperature-induced frequency drifts. Re-evaluating these coefficients periodically corrects for any long-term aging of the quartz crystal.
Environmental Vibration
Extreme high-frequency oscillations from the surrounding environment can excite parasitic modes in the internal crystalline suspension. This interference degrades the accuracy of the quartz resonant accelerometer by introducing noise or causing a bias shift. Isolation mounts are used to damp these high-frequency inputs, protecting the active quartz crystal from structural damage and preventing signal distortion during operation, which ensures the integrity of the guidance data.