Design and test of MEMS gyroscope control system based on LMSD

In order to improve the performance of MEMS gyroscopes, the least mean square demodulation (LMSD) algorithm is utilized in MEMS gyroscope control system. By using Matlab tool, the simulation result shows that the LMSD algorithm has better noise suppression performance than multiplicative demodulation (MD). LMSD algorithm is carried out in field-programmed-gate-array (FPGA) and experimental results are in good agreement with the simulation. Combining with automatic gain control (AGC) and phase-locked loop (PLL) technology, the amplitude variance and phase variance of drive mode are respectively 62ppm and 0.001°. The nonlinearity of scale factor based on LMSD algorithm is 0.068%. Moreover, the gyroscope using LMSD exhibits a bias stability (BS) of 1.8°/h and an angle random walk (ARW) of 0.031°/Vh, better than the BS 6.7°/h and ARW 0.114°/Vh using MD. The experiment proves the feasibility and effectiveness of LMSD algorithm in the digital control system of MEMS gyroscope.