Infrastructure-Less and Connection-Less Ultra-Wideband Ranging Devices

The COVID-19 pandemic created a need for technological solutions that facilitated the application of social distancing measures by automatically measuring the distance between persons. Wearable devices using technologies such as Bluetooth Low Energy (BLE), Ultra Wide Band (UWB), and others started to appear on the market and finding new applications in healthcare and industry. However, insufficient ranging accuracy and high implementation costs limited the practicality of several of these solutions. In this context, we designed a wearable device that uses BLE for connection-less distance measurement orchestration and UWB for distance ranging that does not require pre-installed infrastructure. In this article we report our hardware design and orchestration algorithm together with experimental results on ranging accuracy, energy consumption, and convergence time in the presence of network congestion. Our wearable devices achieved reliable and accurate distance ranging within at most two seconds, with a sufficiently low energy consumption to obtain a usable and practical battery lifetime.