A mobile recording system featuring high-precision time synchronization

Abstract

In mobile environments where recording devices and subjects are in motion, integrating data collected from multiple devices requires precise location and time information. Given that high-precision satellite positioning technology provides centimeter-level accuracy and that movement speeds in mobile environments are around several 10 m/s, the required time accuracy is under 1 millisecond. However, achieving this time accuracy with commonly used devices is not typically feasible. This paper describes a basic architecture to realize time synchronization with less than one millisecond error with an independent recorder using high-precision timing pulses (1-PPS signal) output by a GNSS receiver. Next, we propose a method to precisely identify the image capture time using an optical beacon combining multiple point light sources called GNSS Clock Beacon (GCB). The time of image capture can be determined from GCB images with an accuracy less than or equal to the exposure duration. Finally, we describe an example implementation of a mobile recording system that can be mounted on a motorcycle, which can record time-synchronized data and video with high accuracy using multiple data loggers and video equipment.