MEMS inertial rate and acceleration sensor

Development of the μSCIRAS^TM (pronounced micro-Cyrus) multisensor for a period of over six years has produced a practical MEMS Inertial Measurement Unit (IMU). Using only three silicon sensors, a full-up IMU suitable for tactical grade navigation and guidance applications has been achieved. Iterative improvements in silicon sensor design and bulk micromachining processes have matured to the point where an IMU with an attractive price/performance ratio is now producible. This paper summarizes the design features and test results for an IMU with <100 deg/hr performance. Test results are shown for rate bias and acceleration bias over temperature. Production of this initial member of the μSCIRAS product family begins in 1998 to support applications including guided artillery shells, technology insertion to decrease missile costs, navigation of remotely-piloted vehicles, dismounted soldier location devices and other navigation aids. The small size of this silicon multisensor and its ability to measure both angular rotation rate and linear acceleration provides a useful advantage in product packaging, cost, size, and system testing. The μSCIRAS Inertial Sensor Assembly (ISA) is housed in a 2 cubic inch package weighing less than 5 ounces (140 grams) and requiring less than 0.8 W of power. Continuing development will lead to greatly improved performance on the order of 1 deg/hr at very low prices in high-volume production