Date

2023-1-24

Author

Yeşil, Ferhat

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This dissertation presents a digitally controlled high performance FM MEMS gyroscope system with improved short and long term stability for tactical and near navigation grade applications. The digital gyroscope system has a number of advantages such as simplified electronic hardware, small size, low power, and increased flexibility with software programming for easy configuration for different operation conditions, real-time advanced calibration, and extensive testability. The system is implemented with a low-power microcontroller as opposed to the FM MEMS gyroscope systems implemented with high-power FPGAs in literature, and it is fit into a compact sensor package comparable in the size of the commercial high-performance MEMS gyroscopes so that it can be offered as a commercialized product. The system is developed for a MEMS gyroscope that has a mechanical resonant frequency of about 7.5kHz, which requires digital control loop speeds faster than 75kHz for the 8 implemented digital control loops. These challenging digital control loop speeds are achieved using hardware accelerators and register-level programming methods. The most critical digital control loop is the PLL loop that is used for frequency reading of the FM output, and this loop is carefully designed for obtaining a measurement bandwidth greater than 100Hz which is necessary for the implementation of the Lissajous FM method to achieve an improved bias instability of the gyroscope. The angular random walk (ARW) performance of the gyroscope is improved significantly by using the Lissajous FM method with an asymmetric MEMS gyroscope for the first time in the literature; as this approach allows to obtain an oscillation amplitude ratio of the first and second resonant modes as high as 2500 (as opposed to values lower than 25 in fully symmetric gyroscope structures) which yields to a record high scale factor of 875Hz/(rad/sec), i.e., two orders of magnitude higher than those reported for the FM MEMS gyroscopes in literature. The performance of the FM MEMS gyroscope system is measured to provide an ARW value of 0.52°/hr/√Hz and bias instability value of 0.2°/hr, demonstrating about 6 times better performance for each value of the best FM MEMS gyroscope system reported in the literature implemented with a high-power and bulky FPGA board.

Subject Keywords

MEMS, FM gyroscope, MEMS Gyroscope, Digital Control

URI

https://hdl.handle.net/11511/102556

Collections

Graduate School of Natural and Applied Sciences, Thesis