Direct Frequency-To-Digital Gyroscopes with Low Drift and High Accuracy
The FM gyroscope measures rate directly as a frequency variation and employs rate chopping to reject drift. The scale factor is set by a reference clock. Symmetric and asymmetric readout modes enable trading off long- versus short-term errors without changing the transducer or circuits. Chopped at 10 Hz, the prototype achieves better than 40 ppm scale factor accuracy, 1.5 deg/h1.5 rate random walk in symmetric mode, and 1 mdps/rt-Hz ARW in asymmetric mode.
The authors would like to thank Yu-Ching Yeh, Mithcell Kline, and Parsa Taheri for the transducer design and Yunhan Chen, Ian B. Flader, Dongsuk D. Shin, and Professor Thomas W. Kenny at Stanford University for the MEMS fabrication. Authors acknowledge the support of this project by DARPA under the PASCAL program and thank the TSMC University Shuttle Program for CMOS chip fabrication.
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