MIT researchers have designed a new system that is meant to overcome a longstanding challenge with communication between the air and beneath the water. Wireless underwater sensors are currently unable to share data with sensors on land because the signals able to travel through the air dissipate quickly in the water. At the same time, acoustic signals (sonar) signals sent by underwater devices reflect off the surface of the water without breaking through.
Those facts cause problems in communicating data from underwater exploration or sub to aircraft communications. MIT Media Lab has designed a new system that overcomes that problem. In the system, an underwater transmitter directs a sonar signal at the surface of the water where tiny vibrations are made that corresponds to the 1s and 0s that is being transmitted in the data.
Above the surface of the water, a highly sensitive receiver can read those tiny vibrations and turn the transmission into usable data. The system is called translational acoustic-RF communication or TARF and is still in the early stages of development. Scientists say that despite its early stages, the system is still a milestone and has the potential to open new capabilities in communicating with aircraft from the water.
TARF could have a massive impact for the military where subs would not need to surface to communicate with airplanes and compromise their location. The system certainly has application outside of the military according to the researchers. It could be used on underwater drones that are meant for monitoring marine life to prevent them from having to resurface from deep dives simply to transmit data.
Another potential use would be to locate aircraft that have crashed into the ocean. The aircraft black box could use TARF tech and transmit a signal to the surface to allow the aircraft to be found. TARF uses an acoustic transmitter that uses a standard acoustic speaker. Signals travel as pressure waves of different frequencies that correspond to different bits of data; essentially a 100 Hertz signal would be a 0 and a 200 Hertz wave a 1. The signals cause a ripple in the water only a few micrometers in height that correspond to those frequencies that can be read above the water.