Traceability of digital 3-axis MEMS accelerometer: simultaneous determination of main and transverse sensitivities in the frequency domain

Traceability of digital sensors is a metrological challenge, as well as a present priority, as stated within the emerging metrology requirements for the future in the Strategy 2017 to 2027 document of the Consultative Committee for Acoustics, Ultrasound, and Vibration of BIPM. From this perspective, in this paper, a calibration system for 3-axis digital MEMS accelerometers is described, in order to simultaneously evaluate the main and transverse sensitivities in the frequency domain (from 5 Hz up to 3 kHz) and in static conditions, together with a proper sensitivity parameter for digital outputs, thus providing the required metrological traceability. The procedure, based on the comparison to a reference transducer, involves a single-axis excitation of inclined planes. Experimental results are expressed in terms of exploitation and sensitivities matrices. Overall expanded uncertainties of the main terms are in the order of 2%, in dynamic conditions, and 1%-2% in static conditions. The feasibility of this system can be exploited for the development of manufacturers' in-line control systems and for the investigation of large-scale calibration procedures.