Open standards exist for all manner of wireless and terrestrial communications, but so far none has emerged for underwater communications. Below the waves, submarines, autonomous underwater vehicles (AUVs), and undersea sensor stations use a hodgepodge of incompatible proprietary technologies including acoustic, radio, and optical modems.
Manned submarines and many automated subs can surface to communicate over the air, where the bandwidth is much higher, and some submersible AUVs and research stations can be tethered to floating wireless buoys. Yet, there are times when neither option is feasible, and with the huge expansion in AUVs, there’s a growing need for a universal undersea communication standard for persistent mobile communications.
Internet of Underwater Things
Enter NATO, which has a keen interest in reliably communicating beneath the waves, both for military and emergency response purposes. The multinational defense organization recently announced it has adopted a new JANUS digital communications standard for underwater acoustic modems. Deployed as an official NATO standard called STANAG 4748 (PDF), JANUS will be implemented on all NATO vessels.
As detailed by IEEE Spectrum, the open source, GPL-licensed JANUS standard uses acoustic modems. Acoustic technology has a much longer range than higher-bandwidth optical systems, which top out at 100 meters, and RF radios, which can’t do much better.
JANUS, which is named after the Roman god of gateways, has been tested at 900Hz to 60kHz frequencies at distances of up to 28 kilometers. However, it’s optimized for sending data underwater at up to 10 km.