MIT News August 17, 2018
The laser beams are hampered by significant absorption and scattering in the ocean. Researchers at MIT Lincoln Laboratory are applying narrow-beam laser technology, developed by the Laboratory for the LLCD (Lunar Laser Communication Demonstration), to enable communications between underwater vehicles. A beam from one underwater vehicle is pointed at the receive terminal of a second underwater vehicle. The position calculation is noise sensitive and can quickly accumulate errors of hundreds of meters when a vehicle is submerged for significant periods of time. To overcome this, they implemented an acquisition scanning function that is used to quickly translate the beam over the uncertain region so that the companion terminal can detect the beam and actively lock on to keep it centered on the lasercom terminal’s acquisition and communications detector and establish a link, despite the independent movement of each vehicle underwater. They successfully demonstrated this technique proving the feasibility of the laboratory’s approach to achieving undersea communication that is 10,000 times more efficient than other modern approaches. The work could transform undersea communications and operations in the ocean… read more.
A remotely operated vehicle and undersea terminal emits a coarse acquisition stabilized beam after locking onto another lasercom terminal. Credit: Nicole Fandel