MEMS Tilt Sensor with Improved Resolution and Low Thermal Drift

The purpose of this paper is to investigate the design methodology, test results, and potential applications of a high resolution and low thermal drift calibrated digital inclinometer based on a MEMS capacitive sensor. The inclinometer provides ±10° of measurement range in a rotational plane that is perpendicular to the earth’s gravity and it uses a primary sensing element based on high aspect ratio microstructures, processed by air gap insulated micro structure (AIM) technology. A signal conditioning electronics, processing the MEMS signals, enables flexibility in terms of linearization, thermal compensation and signal calibration. Resolution of ±0.002° has been found around 0° together with a thermal zero drift lower than ±0.002°/°C from 0°C to +50°C. The overall system consumes 15 mA dc current from a 5V supply. Examples of application fields include: platform stabilization, drill orientation, event detection and telematics/GPS.