MOOS middleware and node adaptivity in underwater sensor networks: results from the UAN11 sea trial

The EU funded FP7 UAN - Underwater Acoustic Network - project has among its goals the investigation of networked communication modalities in which mobile nodes are located in the environment to optimize the communication characteristics of the acoustic channel. The mobile nodes in UAN are placed on Autonomous Underwater Vehicles (AUVs) carrying acoustic modems and capable of autonomous decisions. The AUVs must be able to autonomously react to changes in the environment that affect the communication, and to appropriately relocate themselves to guarantee some quality of service performance in the communication task. The autonomous decisions must be taken in a distributed way, also in presence of lack of communication among the network nodes, and must in any case guarantee the fulfillment of a general mission task (surveillance). Each node of the network communicates, at application level, using the MOOS publish/subscribe middleware, which also embeds network security procedures (cryptography, authentication, integrity). This contribution gives implementation details on the integration of the AUVs into the underwater network and reports statistics on the performance of the system obtained during the UAN11 project sea trial, held in Trondheim, Norway, in May 2011. The impact of the introduction of security into network is also discussed.