Apple Inc.
Multi device clock synchronization for sensor data fusion

Abstract:

Immersive audio can be generated and/or updated in real-time as an accessory device presenting the audio is moved with respect to a computing device presenting accompanying video content. This real-time immersive audio is enabled by determining positions of the accessory device with respect to the computing device, based on real-time analysis of sensor information from the accessory device and the computing device. Accurate positions can be determined by synchronizing timestamped sensor data from the multiple devices through the use of a clock of a common wireless communication link (e.g., a Bluetooth connection), which may have lower drift than the global clocks of the devices themselves. Calculated offsets associated with differences between the clock of the wireless communication link and the global clocks of the multiple devices can be used to account for inaccuracies in the global clocks of the multiple devices with respect to one another.