An integrated resonator-based thermal compensation for Vibrating Beam Accelerometers

Although the Vibrating Beam Accelerometer (VBA) shows excellent performances (resolution <; 1 μg), its bias drift over temperature and temperature gradient is a main performance limitation. Numerical compensation can be performed with a temperature sensor in the accelerometer package, but this approach shows two drawbacks for fast measurements: first, there is a time delay between the temperature of the vibrating beam and the temperature of the package, and second the noise level is very high. In order to overcome these limitations, a new structure comprising a second resonator in torsional mode placed in the middle of the vibrating beam was designed. It shows good sensitivity and linearity over temperature and senses the instantaneous temperature of the vibrating beam with low noise, allowing a better compensation of thermal drifts. A new accelerometer with resonator-based thermal compensation was designed, realized and tested. Experimental results confirm the excellence of the torsional mode resonator used as a temperature sensor.