Highly Accurate 3D Pose Estimation for Economical Opto-Acoustic Indoor Localization

By using opto-acoustic indoor localization systems based on ultrasound and infrared, the pose (position and orientation) of multiple objects can be tracked simultaneously when making use of the code-division multiple access (CDMA) technique. This allows the tracking of tools or hand movements in complex manual handling processes in an industrial environment in order to ensure the completeness of the assembly or the pick and place task. This contribution presents such a system with mobile transmitters including four ultrasound piezos and three to five room-fixed receivers. Hence, the 3D position can be determined by unilateral time-of-flight distance measurements between transmitters and receivers. Moreover, the system provides an orientation estimation by using the position signals of multiple transmitters attached to one object. Measurement results for five different poses show an object's center point position error below 2.2 cm across all poses and an orientation error below 17.1. when using five receivers. Those results are obtained using off-the-shelf low-cost narrowband piezoelectric ultrasound transducers without establishing any special laboratory conditions.