Underwater communication and distributed localization of AUV teams

This paper examines a cooperative localization algorithm for teams of Autonomous Underwater Vehicles, as developed within the project THESAURUS. The localization algorithm is strongly dependent on the underlying acoustic communication network, as it only uses acoustic data (range, USBL measurements and transmission of navigation information) to reduce the error and the uncertainty. The localization algorithm is based on the use of an Extended Kalman filter to maintain a model of the entire swarm, while adapting the measurement equation on the basis of the specific measurement available. Simulative results show how the algorithm is effective in fusing the information. The underwater communication networks is based on a time-division multiplexing scheme and on the use of the MOOS pub/sub for application integration. Implementation details of the network are provided, together with a description of how the positioning systems (e.g. USBL) have been integrated within the constraints of the network structure. Preliminary experimental results on localization and communication are provided as obtained from a recent engineering sea trial.