MEMS-based Accelerometers - The Quest for Low Frequencies and Weak Signals

Accelerometers based on a Micro Electro Mechanical System (MEMS) deliver accurate and linear measurements of the ground motion over a large bandwidth (0–800Hz). Such performance has been obtained by using a closed-loop function that minimizes the displacement of a tiny inertial mass to a few nanometers. To improve the signal-to-noise towards the very low frequencies at which the instrument noise increases, a new MEMS has been developed - it provides a significantly lower noise floor (at least −10dB) and thus a higher dynamic range (+10dB). This performance has been tested in a silo that previously housed nuclear missiles and displays high acoustic shielding. This new MEMS sensor will even further ease the detection of low frequencies and of weak signals like those coming from deep targets or from micro-seismic events.