Transport of Underwater Sensor Data

Undersea sensors require means of transporting data to an end-user. Acoustic modem networks are being developed for this purpose, but they are limited by battery power, network priorities, and requirements for clandestine operations. We propose a systemsapproach to reducing the impact on the network of moving large volumes of data, using both low rate and high rate acoustic telemetry, combined with AUV transport of high volume data. We use underwater imagery as a convenient, yet important, source ofdata, with novel and extremely powerful image compression technology to reduce the volume of data to be moved. We employ proven acoustic communications technology and systems to move low volume data through a network, or directly to a gateway. We proposeimplementation of well-understood high rate acoustic communications methods to upload large volumes of data. These techniques are generally unsuited for long range or network links, and require high SNR for good performance. We obtain the requisitebenign channel by acoustic uplink to a nearby, low cost and unique AUV which physically transports the data to a gateway buoy, where it is acoustically uplinked for RF transmission to the end-user.This project will have a major impact on futuredevelopments in acomms network protocols by reducing the complexity of the network and freeing it exclusively for C2 and high-priority applications. It will also impact any discussion of clandestine communications, where that is an operationalconsideration. The very low cost AUV we propose is easily maintained and operated, and may reduce the requirements for human presence in an operational area. The extremely favorable compression ratios we anticipate from the BU algorithms, combined withhigh rate acomms and storage capacity aboard the AUV, will permit the transfer of multiple images without disruption to other parts of a network. We anticipate that the proposed system will lead to the development of data retrieval systems for bothshallow and deep water science programs (e.g., data sampling about deep ocean vents), and will support extensive video imaging with two AUVs, one at depth, one swimming above, with links via RF to end-users ashore.