A Loose Synchronisation Protocol for Managing RF Ranging in Mobile Ad-Hoc Networks

Robot motion coordination and cooperative sensing are nowadays two important and inter-related components of multi-robot cooperation. Particularly, when concerning motion coordination, distance information plays a very important role in mobile robotics. In this work, we investigate a new solution based on ad-hoc communication without global knowledge, particularly clock synchronisation, to measure distance between mobile units and to share that information. In order to improve ranging, medium throughput, and application predictability, we propose using a synchronisation protocol that keeps transmissions in the team as separated as possible in time, independently of the topology. Results show around 3.3 times reduction in the number of failed ranges without external interference and an order of magnitude reduction in the asymmetries among the nodes concerning the number of failed ranges when using the proposed synchronisation protocol.