Aerospace Technology and Low Automotive Costs Benefit Quartz Micromachined Gyros

Asad M. Madni, Lynn E. Costlow and Randall P. Jaffe

Abstract:	In 1835, the French engineer-mathematician Gustave- Gaspard de Coriolis (1792-1843) first described the inertial force now called the Coriolis effect. The effect is an apparent deflection of an object that moves within a rotating coordinate system. The object does not actually deviate from its path, but appears to do so because of the coordinate system motion. The effect is inherent in vibrating tuning fork structures, and is useful in detecting rotation rate. In the 1940s, the Sperry Gyroscope Company developed a tuning fork rate sensor called the Gyrotron, which demonstrated technical feasibility, but was not economically manufacturable. Cost-effective rate gyro production awaited availability of materials and processing technologies compatible with mass-production. Piezoelectric quartz and its high volume use in the crystal oscillator industry provided the right material for the tuning fork. Micromachining techniques, developed in the semiconductor industry since the 1950s, provided a bulk processing technique for a low cost Microelectromechanical System (MEMS) based tuning fork. In addition, mixed signal Application Specific Integrated Circuit (ASIC) technology provided the needed bulk processing and high-density packaging for the signal processing electronics [1]. In the early 1980s, General Precision Industries (GPI), a small R&D organization formed by crystal oscillator industry veterans, demonstrated a piezoelectric quartz tuning fork rate sensor. In 1986, the Systron Donner Corporation of Thorn EMI (now the Systron Donner Inertial Division of BEI Technologies, Inc.), acquired the rights to the promising technology with an exclusive worldwide license. These early beginnings have spawned a mass production of solid state rate gyro product family that has produced in excess of 4,000,000 sensors with an ever-improving price/performance ratio.
Published in:	Proceedings of the 57th Annual Meeting of The Institute of Navigation (2001) June 11 - 13, 2001 Albuquerque, NM
Pages:	205 - 218
Cite this article:	Madni, Asad M., Costlow, Lynn E., Jaffe, Randall P., "Aerospace Technology and Low Automotive Costs Benefit Quartz Micromachined Gyros," Proceedings of the 57th Annual Meeting of The Institute of Navigation (2001), Albuquerque, NM, June 2001, pp. 205-218.
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