Gilbert, Thomas Jamin; Lin, Zexiao; Day, Sally; Hamilton, Antonia F de C and Ward, Jamie A. 2024. A Magnetometer-based Method for In-situ Syncing of Wearable Inertial Measurement Units. Frontiers in Computer Science, 6, 1385392. ISSN 2624-9898 [Article]

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Abstract or Description

This paper presents a novel method to synchronize multiple wireless inertial measurement unit sensors (IMU) using their onboard magnetometers. The basic method uses an external electromagnetic pulse to create a known event measured by the magnetometer of multiple IMUs and in turn uses this to synchronize the devices. An initial evaluation using four commercial IMUs reveals a maximum error of 40 ms per hour as limited by a 25 Hz sample rate. Building on this we introduce a novel method to improve synchronization beyond the limitations imposed by the sample rate and evaluate this in a further study using 8 IMUs. We show that a sequence of electromagnetic pulses, in total lasting <3-s, can reduce the maximum synchronization error to 8 ms (for 25 Hz sample rate, and accounting for the transient response time of the magnetic field generator). An advantage of this method is that it can be applied to several devices, either simultaneously or individually, without the need to remove them from the context in which they are being used. This makes the approach particularly suited to synchronizing multi-person on-body sensors while they are being worn.

Item Type:	Article
Identification Number (DOI):	https://doi.org/10.3389/fcomp.2024.1385392
Additional Information:	Funding: The author(s) declare that financial support was received for the research, authorship, and/or publication of this article. This work was funded in-part by the ERC SocSensors Project (Ref: 899779).
Data Access Statement:	The datasets presented in this study can be found in online repositories. The names of the repository/repositories and accession number(s) can be found in the article/supplementary material.
Keywords:	Wearabe sensors, Synchronization, IMU (Inertial measurement unit), Magnetic field sensor, multisensor
Departments, Centres and Research Units:	Computing
Dates:	Date Event 12 February 2024 Submitted 4 April 2024 Accepted 19 April 2024 Published
Item ID:	35853
Date Deposited:	04 Jun 2024 16:03
Last Modified:	04 Jun 2024 21:11
Peer Reviewed:	Yes, this version has been peer-reviewed.
URI:	https://research.gold.ac.uk/id/eprint/35853

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