Did you know that submarines today still cannot wirelessly communicate with airplanes? For decades, communicating between underwater and the air has remained an unsolved problem. Underwater, submarines use acoustic signals (or SONAR) to communicate; in the air, airplanes use radio signals like cellular or WiFi. But neither of these signals can work across both water and air.
We present TARF (Translational Acoustic-RF communication), the first technology that enables communication between underwater and the air. A TARF transmitter sends standard sound (or SONAR signals). Sound travels as pressure waves; when these waves hit the surface, they cause it to vibrate. To pick up these vibrations, a TARF receiver in the air uses a very sensitive radar. The radar transmits a signal which reflects off the water surface and comes back. As the water surface vibrates, it causes small changes to the received radar signal, enabling a TARF receiver to sense the tiny vibrations caused by the underwater acoustic transmitter.
The video below explains how TARF works and some of its applications.