Long-term gyroscope drift can be effectively removed by employing simultaneous on-chip stress and temperature compensation. Stress effects are significant and their inclusion augments the commonly applied temperature compensation. A silicon-on-insulator… Click to show full abstract
Long-term gyroscope drift can be effectively removed by employing simultaneous on-chip stress and temperature compensation. Stress effects are significant and their inclusion augments the commonly applied temperature compensation. A silicon-on-insulator matched-mode $z$ -axis vibratory-rate gyroscope, as a prototype testbed to study these effects, includes released silicon resistors connected in a Wheatstone bridge as on-chip stress sensors. The gyroscope is ovenized within 300 K ± 20 mK using an external heater and an on-chip temperature sensor to suppress the temperature effects. The gyroscope is in-house vacuum packaged and operated at matched closed-loop drive and sense modes. Stress compensation significantly suppresses long-term drift resulting in 9°/h/$\surd $ Hz angle random walk and 1°/h bias instability at 10 000 s (around 3 h) averaging time, which is seven times improvement over the uncompensated gyroscope output. The sensitivity of zero-rate offset to stress is −0.22°/day/Pa and −0.045°/day/Pa for the tests with and without externally applied stress, respectively.
