Abstract
AntIMU is a way of building a miniature real-time wireless inertial measurement unit by using a pair of 6-DoF inertial sensors collaboratively to achieve better accuracy. AntIMU measures the orientation and trajectory of an object in 3D space by combining two sets of 6-DoF inertial sensors with gyroscope and accelerometer. The combined result improves the tracking accuracy by reducing errors due to drifts and error accumulation from double integration. We experimented with two topologies called Stick-IMU and Frustum-IMU, where we mount the two sets of inertial sensors in the same orientation on two ends of a pole and in different orientations on a trapezoid frustum, respectively. We utilize the orientation diversity and the spatial diversity of relative placement of sensors to get the more precise IMU trajectory estimation. We implemented AntIMU using multiple units of EcoMini, a miniature wireless sensor platform with a radio-enabled microcontroller and a 6-DoF inertial sensor. Experimental results show these two AntIMU to be higher accuracy than the single-EcoMini IMU over several motion patterns. Furthermore, we found that the main cause of errors in IMU trajectory estimation is not sensor noise but the gravity cancellation caused by object movement.