Spring 2014 IAB & Research Review
March 5 - 6
Low Power FM Gyroscopes
MEMS gyroscopes for consumer devices, such as smartphones and tablets, suffer from high power consumption and drift which precludes their use in inertial navigation applications. Conventional MEMS gyroscopes detect Coriolis force through measurement of very small displacements on a sense axis, which requires low-noise, and consequently high-power, electronics. The sensitivity of the gyroscope is improved through mode-matching, but this introduces many other problems, such as low bandwidth and unreliable scale factor. Additionally, the conventional Coriolis force detection method is very sensitive to asymmetries in the mechanical transducer because the rate signal is derived from only the sense axis. Parasitic coupling between the drive and sense axis introduces unwanted bias errors which could be rejected by a perfectly symmetric readout scheme. In this talk, I will present frequency modulated (FM) gyroscopes that overcome the above limitations. FM gyroscopes also promise to improve the power dissipation and drift of MEMS gyroscopes. I will present results from a prototype FM gyroscope with integrated CMOS readout electronics demonstrating the principle.