In fields such as inertial navigation, drone control, and smart wearables, the measurement accuracy of MEMS gyroscopes directly determines system performance. However, due to factors such as packaging stress, temperature drift, and zero-bias error, MEMS gyroscopes are prone to data deviations after leaving the factory. Temperature-controlled turntables, as dedicated calibration equipment , can eliminate system errors through standardized procedures, allowing the gyroscope to return to its optimal measurement state. This article details the core steps and key technologies for calibrating MEMS gyroscopes using a temperature- controlled turntable, helping engineers efficiently complete calibration work.

I. Preparations before calibration: Dual verification of equipment and parameters

Accurate calibration requires a stable testing environment, and the core preparation work revolves around "equipment matching" and "state reset":

Equipment selection and connection : Select a temperature-controlled turntable with an angular rate range covering the gyroscope measurement range (typically ±1000°/s to ±20000°/s) and an angular position accuracy ≤0.001° ; complete data communication between the turntable and the gyroscope through an RS485/USB interface, and connect to a temperature control system to stabilize the ambient temperature at 25℃±2℃ (to eliminate temperature interference).

Gyroscope preprocessing : Fix the MEMS gyroscope to the center mounting platform of the turntable, ensuring that the mounting surface is perpendicular to the rotation axis of the turntable (coaxiality error ≤ 0.02mm); preheat for 30 minutes to allow the internal circuitry of the gyroscope to reach thermal equilibrium and avoid initial temperature drift from affecting the calibration data.

Reference parameter setting : Input basic parameters such as gyroscope model, nominal sensitivity (e.g., 10mV/(°/s)), and zero bias voltage into the turntable control system, adjust the standard calibration protocol (e.g., IEEE 1554.2), and complete the parameter matching between devices.

II. Core Calibration Process: Full-Dimensional Calibration from Static Zero Bias to Dynamic Rate

The temperature-controlled turntable achieves comprehensive calibration of the gyroscope's zero bias, sensitivity, and nonlinear error through a combination of static positioning and dynamic rotation. The core process consists of three steps:

1. Static zero-bias calibration: Eliminating static error reference

Zero bias error is the output drift of a gyroscope when it is stationary, and it is a key factor affecting the accuracy of static measurements. The temperature -controlled turntable was kept stationary (angular rate = 0°/s), and gyroscope output data was continuously collected for 10 minutes. A voltage value was recorded every 10ms, and the average zero bias was calculated using the following formula:

Zero bias V₀ = (Σ Vᵢ ) / n ( i = 1 to n , where n is the total number of data sets)

Outliers exceeding the range of 3σ ( σ being the standard deviation) are removed , and the final zero bias value is used as the benchmark for subsequent data correction.

2. Dynamic sensitivity calibration: Establishing a linear relationship between input and output.

Sensitivity is the ratio of the gyroscope's output change to its input angular rate; calibration must cover its full range. The temperature- controlled turntable is rotated uniformly at five characteristic angular rates (e.g., 100°/s, 500°/s, 1000°/s, 1500°/s, 2000°/s). After stabilizing for 3 minutes at each rate, data is collected, and the average output voltage Vᵢ corresponding to each rate is calculated .

Sensitivity K = ( Vᵢ - V₀ ) / ωᵢ ( ωᵢ is the set angular velocity of the turntable)

with ωᵢ as the horizontal axis and ( Vᵢ - V ₀) as the vertical axis. Calculate the linear fitting equation using the least squares method to ensure that the goodness of fit R² ≥ 0.999. The slope at this point is the actual sensitivity after calibration.

3. Nonlinear error calibration: Corrects deviations across the full measurement range.

Based on the sensitivity calibration, add 10 uniformly distributed angular velocity points (e.g., 200°/s, 400°/s...1800°/s), repeat the dynamic data acquisition process, and calculate the deviation between the actual output and the linear fitting value at each point:

Nonlinear error δ = [( _actual V - _fitted V ) / ( full scale V - V₀ )] × 100%

If δ exceeds the gyroscope's performance requirements (usually ≤0.5%), an error compensation coefficient needs to be applied through the turntable control system to achieve nonlinear correction across the full range.

III. Post-calibration verification: A key step in ensuring data reliability

After calibration, the system must pass both "recalibration verification" and "scenario testing" verifications.

1. Recalibration and verification : Randomly select 3 angular rate points (e.g., 300°/s, 800°/s, 1600°/s), repeat the dynamic calibration process, and compare the sensitivity and zero bias of the two calibrations. The deviation must be ≤0.1%. Otherwise, the installation accuracy and data acquisition link need to be rechecked.

2. Scenario testing : Connect the calibrated gyroscope to the inertial measurement unit (IMU), simulate the attitude changes of the drone (such as ±30° pitch and rotation) through a temperature-controlled turntable, collect the angular position data output by the gyroscope, and compare it with the standard angular position of the turntable. The error should be controlled within 0.01°.

Through standardized calibration using a temperature-controlled turntable, the zero-bias stability of MEMS gyroscopes can be improved by more than 50%, and the sensitivity error can be controlled within 0.1%, providing a core guarantee for the accurate operation of subsequent systems.