Si-MEMS gyro by Safran: Towards the navigation grade

Prolonging the pioneering works initiated in the 60’s [1], [2] and bringing radical innovations such as planar electrodes, Safran Electronics & Defense has successfully achieved a major technological breakthrough by developing and industrializing a navigation-grade Inertial Navigation System (INS) technology based on HRG Crystal™. Further optimization of the Cost Size Weight And Power (CSWAP) implies the development of a navigation grade MEMS gyroscope. Safran decided to take up the challenge. In this paper, we introduce a design evolution which has brought great performance results. While keeping an axisymmetric design and a fully balanced gyro mode [3], the innovation relies on electrostatic transducers now located between the vibrating masses. In the first part of this paper, we describe the key design rules and the innovation brought on electrostatic transducers location. The second part deals with the technological implementation of this new design on a silicon MEMS die. Finally, test results are presented with a special focus on performances under external vibrations.