Nowadays, not only wearable and portable devices but also aerial and ground robots can be made smaller, lighter, cheaper, and thus as large as hundreds of them may form a swarm to participate in a complicated cooperative application, such as searching, rescuing, mapping, and war-battling. Devices and robots in such a swarm have three important features, namely, large number, high mobility and short distance, hence they form a dynamic and dense wireless network. Successful swarm cooperative applications require low latency communications and real-time localization. This paper proposes to use ultra-wideband (UWB) radio technology to implement both functionalities, because UWB is very time-sensitive that an accurate distance can be calculated using the transmission and reception timestamps of data messages. A UWB swarm ranging protocol is designed to achieve simultaneously wireless data communication and swarm ranging that allows a device/robot to compute the distances to all the peer neighbors at the same time. This protocol is designed for dynamic and dense networks, meanwhile it can also be used in various wireless networks and implemented on various types of devices/robots including low-end ones. In our experiment, this protocol is implemented on Crazyflies, STM32 microcontroller powered micro drones, with onboard UWB wireless transceiver chips DW1000. Extensive real-world experiments are conducted to verify the proposed protocol on various performance aspects, with a total of 9 Crazyflie drones in a compact area. The implemented swarm ranging protocol is open-sourced athttps://github.com/SEU-NetSI/crazyflie-firmware

Nowadays, aerial and ground robots, wearable and portable devices are becoming smaller, lighter, cheaper, and thus popular. It is now possible to utilize tens and thousands of them to form a swarm to complete complicated cooperative tasks, such as searching, rescuing, mapping, and battling. A swarm usually contains a large number of robots or devices, which are in short distance to each other and may move dynamically. So this paper studies the dynamic and dense swarms. The ultra-wideband (UWB) technology is proposed to serve as the fundamental technique for both networking and localization, because UWB is so time sensitive that an accurate distance can be calculated using timestamps of the transmit and receive data packets. A UWB swarm ranging protocol is designed in this paper, with key features: simple yet efficient, adaptive and robust, scalable and supportive. This swarm ranging protocol is introduced part by part to uncover its support for each of these features. It is implemented on Crazyflie 2.1 drones, STM32 microcontrollers powered aerial robots, with onboard UWB wireless transceiver chips DW1000. Extensive real world experiments are conducted to verify the proposed protocol with a total of 9 Crazyflie drones in a compact area.