Wireless time synchronization is one of the most important services in a Wireless Sensor Network (WSN). Inertial Measurement Units (IMUs) are often used in these WSNs in healthcare-related treatments. We present a low-power, wirelessly synchronized multi-IMU platform. The proposed approach synchronously captures packets from different IMUs and transmits the data over Bluetooth Low Energy (BLE) to a central Data Capturing Unit (DCU). The contribution of this work is, rather than focussing on the highest possible accuracy, to provide a low-power accurate enough solution for use in a multi-IMU WSN. We examine key factors affecting synchronization accuracy and elaborate on the implementation challenges. An accuracy of sub 1 us can be achieved with the approach using 74.8 J/h of energy, while a power-optimized implementation is presented with an accuracy of 200 us and an energy consumption of only 198 mJ/h. This approach suits the required accuracy and low-power requirements for a multi-IMU system.

翻译：无线时间同步是无线传感器网络（WSN）中最重要的服务之一。惯性测量单元（IMU）常用于这些WSN中的医疗相关治疗。我们提出了一种低功耗、无线同步的多IMU平台。该方法同步捕获来自不同IMU的数据包，并通过低功耗蓝牙（BLE）将数据传输至中央数据采集单元（DCU）。本工作的贡献在于，并非追求最高精度，而是为多IMU WSN提供一种低功耗、足够精确的解决方案。我们研究了影响同步精度的关键因素，并详细阐述了实现中的挑战。采用该方法可实现亚微秒精度，能耗为74.8焦耳/小时；同时提出了一种功耗优化实现，精度为200微秒，能耗仅为198毫焦耳/小时。该方法满足多IMU系统对精度和低功耗的需求。