Precision of inertial measurement unit sensors in head-tracking systems used for binaural synthesis

Binaural synthesis is the most used sound system for diverse virtual and augmented reality systems nowadays, given its simplicity of implementation and the need of using only two audio channels. It is widely used in computer games, auralization and even audio production. To achieve the most natural sound field recreation, systems used for binaural synthesis must include a head-tracking sensor to dynamically calculate the binaural signal for the head orientation at any given moment. This is done by inertial measurement unit (IMU) sensors, specifically the triaxial accelerometers, gyroscopes, and magnetometers. Simpler systems, e.g., Arduino or other embedded systems, provide only raw sensor data, and the orientation is calculated by a processing unit. Other, more complex systems such as smartphones or VR headsets already calculate their position from the raw data using complex sensor integration algorithms. In this paper, a measurement procedure for measuring the precision of IMU sensors is presented. The need of absolute orientation calibration is addressed, and challenges of sensor data drift are discussed. Measurement results for simple embedded systems and complex systems found in smartphones are presented, and an estimation of IMU sensor quality for binaural synthesis is made.