Improvement of the Hemispherical Resonator Gyro Performance

Yuri Zhbanov

Abstract:	The drift of Hemispherical Resonator Gyro (HRG) is con- sidered which is caused by asymmetric damping depend- ing on the position of standing wave relative to the res- onator. A new method is proposed for the identification of the mismatch in damping during the HRG operation. The method is based on the analysis of control signals in the system for sustaining of an amplitude of resonator oscillations required. The information about asymmet- ric damping used in the HRG control system allows to improve the HRG performance. The average Q-factor is found along with the mismatch in damping. That allows to improve the performance of the amplitude con- trol loop. The same method applied for the analysis of control signals in quadrature control loop makes possible to identify the mismatch in natural frequencies. HRG is one of the most promising gyroscopic sensors. The first publication concerning physical principles of HRG goes back to 1890. The first patents were issued in the U.S.A. in the 1970s. In the EOS journal (#l, 1995) a paper by David D. Lynch was published in which the physics, design, and specific features of functioning of this device were expounded in detail. David D.Lynch is the author of many of the American patents related to HkG. In Russia, the theory of HRG has been developed mostly in works by Prof. V. Ph. Zhuravlev and Academi- cian D. M. Klimov. Let us recall the physical principles of operation of HRG. In a thin hemispherical quartz shell, whose top is fixed, a standing elastic wave is excited. The wave has four nodes and four antinodes on the shell edge. When the shell rotates about an axis perpendicular to the plane of the shell edge, the wave goes behind the shell in an inertial space by an angle proportional to the angle of rotation of the shell in the inertial space. The angle of rotation of the wave pattern with respect to the shell or, more precisely, with respect to the housing, serves as the output signal of the device.
Published in:	Proceedings of the 53rd Annual Meeting of The Institute of Navigation (1997) June 30 - 2, 1997 Albuquerque, NM
Pages:	365 - 367
Cite this article:	Zhbanov, Yuri, "Improvement of the Hemispherical Resonator Gyro Performance," Proceedings of the 53rd Annual Meeting of The Institute of Navigation (1997), Albuquerque, NM, June 1997, pp. 365-367.
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