Anthony S. Kourepenis

A micromachined comb-drive tuning fork rate gyroscope

The development of single-crystal and polysilicon tuning fork gyroscopes of very small size and low cost using microfabrication technology is reported. These tuning fork gyroscopes are extremely rugged, inherently balanced, and easy to fabricate. For a 1-mm gyroscope, projected performance is 10 to 100 degrees /hr for bias stability and for resolution in a 60-Hz bandwidth. To date, 5000 degrees /hr in a 60 Hz bandwidth has been demonstrated. The principle of operation, projected and measured performance and fabrication of silicon, polysilicon, and nickel units and associated electronics and control issues are discussed.<<ETX>>

Error sources in in-plane silicon tuning-fork MEMS gyroscopes

This paper analyzes the error sources defining tactical-grade performance in silicon, in-plane tuning-fork gyroscopes such as the Honeywell-Draper units being delivered for military applications. These analyses have not yet appeared in the literature. These units incorporate crystalline silicon anodically bonded to a glass substrate. After general descriptions of the tuning-fork gyroscope, ordering modal frequencies, fundamental dynamics, force, and fluid coupling, which dictate the need for vacuum packaging, mechanical quadrature, and electrical coupling are analyzed. Alternative strategies for handling these engineering issues are discussed by introducing the Systron Donner/BEI quartz rate sensor, a successful commercial product, and the Analog Device (ADXRS), which is designed for automotive applications.

Microelectromechanical instrument and systems development at the Charles Stark Draper Laboratory, Inc

Draper Laboratory and Boeing North American have formed an alliance to develop very small, low-cost rate sensors for commercial and military applications. Several generation of micro-mechanical gyroscopes have been developed at Draper, using a dissolved wafer process that features single crystal Si anodically bonded to a glass substrate. Resulting sensor die size is approximately 1 mm. When integrated with applications specific integrated circuits (ASICs), the sensor fits in a 3 cm per side flat pack operating from a single 5V dc supply. Bias stability over temperature ranges of 0.5/spl deg/C has surpassed 10/spl deg//hr. Best to date resolution and angle random walk performance is 25/spl deg//hr in 60 Hz and 0.04/spl deg///spl radic/h respectively. The sensors are extremely robust, having survived air guns tests in excess of 60,000 gs. This technology is useful for spacecraft inertial guidance. Size, mass, and power of inertial systems can be reduced by orders of magnitude, providing benefits of paramount importance to the new class of miniature satellites, revers, and spacecraft. However, significant challenges remain before this technology is routinely available for space applications related to performance and space environmental effects. This paper discusses the principle of operation, measured and projected performance, and approaches being taken at Draper Laboratory to develop micromechanical instruments suitable for use in military and space systems.

Micromechanical inertial guidance navigation and control systems in gun launched projectiles

Micromechanical technology applied to inertial instruments opens up many new applications where cost, size and power are important. One very important application is the guidance, ‘* navigation and control of gun launched projectiles. In order to be affordable these systems must cost less than

Performance of MEMS inertial sensors

2,000, have very low power requirements and eventually fit into a standard NATO Fuze of 9 cubic inches, including all fuzing and safe and arming functions. Since 1997 when Draper demonstrated the fast successful launch from a Navy 5” gun of a Micromechcanical Inertial Measurement Unit and Global Positioning System (MMIMU/GPS) in a rocket assisted 5” projectile many new applications have been identified and are being pursued. Draper is presently ready to flight test a MMIMUIGPS in a spinning 5” projectile with the system despun in the nose mounted fuze assembly. This paper will describe the application of this technology to Navy and Army projectiles, both spin stabilized and non-spinning. Some of the projectiles described will be the Navy’s Extended Range Guided Munition (ERGM) Demo, the Army’s Precision Guided Mortor Munition (PGMM) 120 mm projectile and standard NATO Fuze applications to spin stabilized projectiles such as existing S’, 155mm, 12Omm, etc.