The Kongsberg Maritime Subsea division in Horten has been conducting a development program for using cNODE in a network configuration, enabling it to interface to various sensors, and communicate sensor data via wireless among other nodes in the actual network. In addition to tele- metry functionality, cNODEs are also intended for navigation and positioning usage. In-house product development of cNODE as well as collaborative projects like NNN-UTS completed in 2010 followed by a UAN project are still ongoing.
Introducing network configuration for acoustic communication opens up a range of applications: Long distance communication can be performed by relay messages between several nodes. Another example is to monitor a designated subsea area with a network of cNODEs with integrated sensors; this data will be available real time.
One of the cNODEs in the network is designated to be a master node, and can be connected to a satellite communication link for transfer of data. Subsea the network is self configuring.
Folaga AUV carrying cNODE during test of communication networkHiPAP and cPAP can be used for communication with the network and the cNODEs can be used for both positioning and telemetry purposes. cNODEs with floating collar are easily deployed and picked up since they have an acoustic release functionality, controlled via their own acoustic link. Operating depth could be down to 4000 m water.
The network also supports mobile nodes, an example of this could be an AUV with a cNODE aboard. Suitable applications for cNODE networks would be ocean monitoring of environmental and marine biological parameters, and detecting and monitoring industrial parameters around offshore installations, for example pressure and temperature or gas leakage.
In collaboration with partners on the UAN project, an at sea test of an acoustic wireless network based on cNODE was carried out in the Trondheimsfjord from May 18th -27th.
"The network sea test included six cNODEs, two of them mounted on AUVs. The team experienced challenging sound profiles in Trondheimsfjorden due to layers of fresh river water. Nevertheless we got proof that the cNODE network features are working," says Thor Storm Husøy, project manager from Kongsberg Maritime Subsea, Horten.