A batch-mode assembly and packaging technology for 3-axis tri-fold inertial measurement units
This paper reports a batch-mode generic 3-D precision assembly and wafer-level packaging technology for 3-axis tri-fold inertial measurement units (IMUs) using silicon mounting jig wafers with embedded vacuum channels. This approach allows use of optimized single-axis IMUs without manufacturing and structural constraints of forming 3-axis in a chip, and improving the overall yield by testing the chips prior to 3-D assembly. The 3-D chip assembly is performed by a controlled sequence of vacuum through the channels and bottom access holes, ambient pressurization, and raise of temperature to form permanent rigid tri-fold bond to the jig wafer.
Honeywell gun-hard inertial measurement unit (IMU) development
Honeywell has designed and manufactured a gun-hard IMU that provides the baseline for meeting the needs of DoD guided tactical munitions, as well as being a platform for commercial usage. The gun-hard IMU is a solid-state inertial sensor package that measures and provides inertial angular rates and linear accelerations in a body-mounted strap-down mechanization. Its compensated outputs include summed and incremental angle and velocity data for inertial guidance, as well as angular rates and linear accelerations for autopilot/control functions. The data are reported in user-defined coordinates at 600 Hz and 100 Hz (typically) through a digital serial interface bus. The unit contains three Honeywell MEMS silicon gyroscopes, three Honeywell MEMS silicon accelerometers, as well as the electronics and software necessary to implement the requirements of the tactical market. The Honeywell gun-hard IMU development team includes multiple Honeywell sites and Draper Laboratories. In 2003, Honeywell demonstrated IMU survival and performance above 10,000 g's. In 2004, Honeywell will produce and deliver an IMU that will survive and perform at 20,000 g's. In addition to providing gun-hard survivability and high performance, Honeywell will capitalize on its extensive production experience to ensure a device that is cost effective for Honeywell customers.
Low cost, high G, micro electro-mechanical systems (MEMS), inertial measurements unit (IMU) program
Precision guided munitions (PGMs) are critical to the Maneuver Battalion Commander's success on future rapidly deployed battlefields. These PGMs will provide an increase in lethality, significantly improve survivability, reduce collateral damage, minimize non-combatant casualties, and decrease the logistics burden or increase the number of kills from the standard logistics load. PGMs all require inertial measurement sensors embodied in an IMU. Until now, they have been large, expensive, and could not readily survive the high G launch environments. MEMS technology provides inherent cost savings and size reduction and is ideal for application to navigation and control systems for small missiles and munitions. Using MEMS technology, gyroscopes, accelerometers and control electronics can readily be integrated to form a tightly packaged, low-cost, extremely small, high performance IMU suitable for munition, missile, and personnel guidance as well as other applications. This paper describes the current Army development underway and its partnership with industry to achieve the necessary requirements. The program goal is to survive a 20,000 g gun launch and meet a 1/spl deg//hr, 1/2 milli-g performance capability. The MEMS IMUs will significantly reduce the cost of precision-delivered missiles and munitions, as well as expand precision delivery capability to artillery ammunitions, and thus reduce the number of required rounds by more than 30% while meeting roughly 90% of the tactical weapons fleet navigational requirements.