Undersea communication network self-localization during the Unet´08 seatrial

The U.S. Navy Seaweb project has been advancing the state-of-the-art in undersea acoustic networks over the past decade. Seaweb utilizes commercially available telesonar modems and has developed link/network layer firmware to provide a robust undersea communications capability. Gateway technologies and a Seaweb server have been successfully developed. Over 50 successful deployments of Seaweb networks have been made, most focusing on engineering development of the system, while others were interfaced to various Navy applications for demonstration. Recent progress has been made in enhancing the autonomy of these undersea communications networks. Seaweb networks now have the capability to perform self-discovery and establish the connectivity of the network autonomously. A byproduct of the self-discovery process is the set of inter-nodal range measurements for nodes that have communication connectivity. With this information, a centralized control node may estimate the localization of the network layout, subject to some constraints. This paper provides an overview of the Seaweb undersea networking capability and describes the localization algorithm. Its limitations and constraints are also discussed. The algorithm is applied to actual experimental data collected by a Seaweb network deployed during the Unet´08 sea trial. Results are shown for two network topologies deployed during that trial.