Improved Scale-Factor and Bias Stability of Ovenized Inertial Sensors in an Environmentally-Stabilized Inertial Measurement Unit (eIMU)

This paper reports on scale-factor and bias stability improvements for a commercial 6-axis inertial measurement unit (IMU) enabled using oven-stabilized “environment-resistant packaging (ERP).” Precise temperature control of the IMU die is accomplished using an in-package isolation substrate with thermal isolation for low-power heating. This substrate also isolates the sensors from system-level mechanical stresses. The resulting ovenized device is known as an Environmentally-Stabilized Inertial Measurement Unit, or eIMU. For the first time., a population of eIMU devices has undergone rigorous third-party testing to quantify the performance of the eIMU compared to the same IMU in its standard manufacturer package. The results indicate a 13-115 x improvement for scale-factor vs temperature and a 6-40 x improvement for bias repeatability vs. temperature for the 3 gyroscopes and 3 accelerometers in the IMU. In addition., the eIMU shows 12-44 percent improvement in bias stability for each of these sensors and up to 19 x improvement in long-term drift.