Allan variance analysis on MEMS tilt sensors with different principles of operation

Tilt sensing is an important part in absolute position and orientation measurement, e.g. inertial navigation units and tilt detectors. In this paper, the direct comparison of three MEMS tilt sensors with different principle of operation has been carried out and evaluated using Allan variance (AV) method. Selected samples represent major principles used in MEMS accelerometers on the market - capacitive Analog Devices ADXL203, thermal MEMSIC MXA6500M and piezoresistive Panasonic AGS61231. All devices have similar measurement range and acceleration sensitivity. The results of AV analysis show similar behavior and curve shape in capacitive principle, with the lowest acceleration random walk observed, and in thermal principle, with six times higher bias instability in compare with capacitive principle. The piezoresistive principle has lower velocity random walk, but it is very sensitive to temperature variations, seen in long cluster times.