text: 355,64,1238390910846742528,3021399517,Jean-Baptiste Mouret,"New paper: we designed an algorithm that allows miniature underground UAVs to establish communication relays in tunnels. Paper: <LINK> We use the nice Crazyflies by @Bitcraze_se. <LINK> @Bitcraze_se Thanks. If you are interested, we could write a blog post about this (in particular, we have actual p2p communication and everyting runs on the crazyflies)",https://arxiv.org/abs/2003.04409,"Miniature multi-rotors are promising robots for navigating subterranean networks, but maintaining a radio connection underground is challenging. In this paper, we introduce a distributed algorithm, called U-Chain (for Underground-chain), that coordinates a chain of flying robots between an exploration drone and an operator. Our algorithm only uses the measurement of the signal quality between two successive robots as well as an estimate of the ground speed based on an optic flow sensor. We evaluate our approach formally and in simulation, and we describe experimental results with a chain of 3 real miniature quadrotors (12 by 12 cm) and a base station. ","Signal-based self-organization of a chain of UAVs for subterranean