Bias-Repeatability Analysis of Vacuum-Packaged 3-Axis MEMS Gyroscope Using Oven-Controlled System

Area of Science:

• Engineering
• Materials Science
• Physics

Background:

• Microelectromechanical System (MEMS) inertial measurement units (IMUs) performance is significantly impacted by environmental factors, particularly temperature.
• Bias stability variations in MEMS gyroscopes pose a challenge for accurate navigation.
• Commercial MEMS IMUs require compensation strategies to meet stringent performance specifications.

Purpose of the Study:

• To analyze and improve the bias stability of a commercial MEMS gyroscope.
• To investigate the effectiveness of a micro-heater and PID/PWM control system for temperature compensation.
• To evaluate the impact of vacuum packaging on gyroscope bias repeatability.

Main Methods:

• Integration of a gold (Au) thin film micro-heater with a commercial BOSCH BMI 088 MEMS IMU.
• Development of a custom micro-machined glass platform for thermal isolation and vacuum sealing.
• Utilization of the IMU's built-in temperature sensor for closed-loop temperature control.
• Comparison of bias repeatability between vacuum-packaged and non-vacuum-packaged devices.

Main Results:

• Significant improvement in bias repeatability of the MEMS gyroscope, achieving target specifications for navigation.
• Demonstration of effective bias compensation using the integrated micro-heater and PID/PWM control system.
• Over 60% improvement in bias repeatability for vacuum-packaged devices compared to non-vacuum-packaged ones.

Conclusions:

• The ovenized MEMS gyroscope system effectively compensates for temperature-induced bias variations.
• The developed thermal management and control strategy enhance MEMS IMU performance for navigation.
• Vacuum packaging is crucial for maximizing bias stability improvements in MEMS gyroscopes.