Designing Thermal Soak Chambers for Inertial Sensor Allan Variance Characterization
Precision Allan variance characterization demands thermal soak chambers featuring sub-millikelvin temperature stability, low vibration, and zero fluid turbulence.
Inertial Sensor Characterization
Metrological Assessment
Precision navigation instruments require systematic measurement of systematic and stochastic errors to ensure positioning accuracy. Inertial sensor characterization is the process of defining the deterministic and random biases of accelerometers and gyroscopes. This procedure establishes the operational baseline for calibration algorithms.
Systematic Evaluation
Multi-axis rate tables with precise angular positioning are used to measure scale factor and axis misalignment. During inertial sensor characterization, the device is subjected to known rotational profiles and linear accelerations under controlled environmental conditions. The resulting output profiles are analyzed using Allan variance to separate white noise from bias instability.
These results are compiled into a calibration coefficient matrix.
Thermal Influence
Temperature chambers mounted on the rate tables allow assessment across the full industrial temperature range. Because thermal gradients induce drift, characterization profiles must map bias changes at rate increments of less than five degrees Celsius per hour. This thermal mapping allows active compensation during operation.
The resulting lookup tables are flashed to the sensor memory to correct for temperature-induced offset during field deployment.
Verification Protocol
Factory verification is performed using a high-stability quartz reference accelerometer to trace measurements back to national standards. Testing is completed at specific thermal and physical test steps to assure measurement repeatability.