Ovenized Inertial Micro Electro Mechanical Systems

IMUs consist of 3 accelerometers (which measure motion in a straight line) and 3 gyroscopes (which measure angle changes). Working together with the correct software, they can be used for navigation and orientation measurements in a wide range of applications. Microelectromechanical systems (MEMS) inertial (motion) sensors are now used for a wide range of consumer, industrial and automotive applications, but cant be used for higher performance applications because of their extreme environmental sensitivityespecially to temperature. In particular, the measurement (bias) stability of consumer grade gyroscopes can be up to 80 degrees per hour per degree Celsius. This means that even with small outside temperature changes, these sensors cannot maintain bias repeatability of under 20 degrees per hour required for many tactical navigation applications. The proposed environment resistant inertial measurement unit (eIMU) addresses this by applying a stress isolation and thermal control package around a MEMS IMU in order to: 1) maintain a constant temperature during operation and 2) isolate it from humidity and outside stresses in the environment. The technical challenges include: i) choosing the optimal IMU for packaging in order to address military applications; and ii) improving the package design for better stress/thermal isolation and better stress repeatability.