Tactical grade MEMS gyro with low acceleration sensitivity

Abstract

MEMS gyros have sensitivity to acceleration due to asymmetry of their mechanical designs and/or micromachining inaccuracies. This paper describes a tactical grade MEMS gyro with superior acceleration rejection. The MEMS gyro structure has two proof masses and 12 modes. The effects of low-order modes on the gyro were studied by theory analysis and vibration experiments. The gyro modes were reordered with a new anchor beam structure and optimized structural parameters. The gyro structure was fabricated with SOI technology and packaged with wafer level vacuum packaging. The gyro die and ASIC die were stacked assembly in the ceramic package, and the volume is 11.4×11.4×3.8mm3. The gyro's operating rang is ±300°/s, scale factor nonlinearity is 136.6ppm, the bias stability is 1.3°/h (1σ) and the bias repeatability is 0.8 7h(1σ). The g sensitivity and g2 sensitivity are 6.9°/h/g and 0.2°/h/g2 respectively.