Optimal Swarm Ranging Protocol for Dynamic and Dense Ultra-Wideband Networks

Nowadays, as mobile robots and devices become smaller and lighter, forming them into swarms to collaboratively complete tasks has become an important research area. The previously introduced Ultra-Wideband (UWB) Swarm Ranging (SRv1) protocol pioneered simultaneous data transmission and ranging. However, it suffers from performance degradation in large-scale robot or device swarms.This paper introduces Swarm Ranging 2.0, a fundamentally redesigned and theoretically optimal protocol, which pushes the DS-TWR method to its theoretical limit, maximizing the number of distance calculations. Firstly, we propose a novel compensatory ranging method, enabling additional ranging for dynamic swarms. Next, we analyze the primary packet loss scenarios and redesign the ranging message and ranging table (data structure) to achieve robust ranging. Subsequently, to cope with complex combinations of packet loss and inconsistent frequency, we model the new protocol using a state machine. Theoretical analysis further proves its optimality. We implement the protocol on Crazyflie 2.1 drones equipped with DW3000 UWB transceivers. Experiments with 25 drones show a 47.8% improvement over SRv1 and over 300% improvement compared to standard UWB protocol, demonstrating the protocol’s scalability and effectiveness in real-world swarm deployments. The protocol is open-sourced at https://github.com/SEU-NetSI/crazyflie-firmware.