Absolute pitch, roll and yaw measurement on CMOS

This paper introduces a unique combination of pitch, roll and yaw sensors on a fully monolithic CMOS chip. Pitch and roll are measured using two identical heat transfer based tilt sensors while yaw is derived from an original micromachined compass. Contrary to systems based on gyroscopes, it outputs the absolute values of the three angles. All three sensors are fabricated simultaneously using a cheap one-step auto-aligned post process (front side bulk micromachining), thus addressing high volume markets. On the first prototype, the measured resolution is about 1.7deg for pitch and roll with a time response of 30 ms and 2deg for yaw with a time response of only 10ms. These characteristics can be improved by on-chip signal processing (targeted resolution for yaw is 0.1deg with a time response of 50ms). Such sensors association has numerous identified applications in the field of mobile devices: compass with tilt compensation; pointing devices or new functionalities in mobile phones to mention few