Digital architecture for vibrating inertial sensors: modularity, performances, self-calibrations

This paper presents a fully integrated inertial instrument composed of a vibrating sensor and a Field-Programmable Gate Array (FPGA) device. This digital architecture ensures the electronic driving of the resonator and its response measurement in a reduced space. The current FPGA performances allow to easily adjust frequency, phase and magnitude of the excitation respectively better than 1 μHz, 10 μrd, and 0,01 % of full scale. Therefore, this architecture is especially suitable to the use of feedback-control loops. The instrument is connected to an On Board Computer by serial communication. The performances obtained with this architecture are 0,8 μg bias instability, 60 μg of residual thermal bias stability for the accelerometer, 1 °/h bias instability, and 0,03 ° /√h angular random walk for gyroscope.