Metrological traceability of a digital 3-axis MEMS accelerometers sensor network

Traceability of digital 3-axis MEMS accelerometer networks is often disregarded by manufacturers and end-users due to the lack of suitable calibration procedures and to the complexity in managing a large number of sensitivities. To overcome these problems, two traceable independent accelerometer calibration systems and methods using inclined planes have been recently developed by a national metrology institute and a calibration laboratory at an uncertainty level of 2 %. In this work, main and transverse magnitude sensitivities of 25 digital 3-axis MEMS accelerometers, part of a sensor network prototype conceived for structural monitoring at low-frequencies, are evaluated at three low-frequencies by the two laboratories. Comparison shows compatible results. Furthermore, a method for decreasing the number of sensitivity and uncertainty data to be managed by sensor network end-users is also proposed. It is shown that its number can be reduced preserving the required traceability at the expense of higher uncertainties up to 4.5 %.