Chinese scientists develop long-distance underwater communication in South China Sea
- Researchers say innovation would allow submarines and drones to maintain contact over more than 30,000 sq km (11,600 square miles) and aid communication with smart weapons
- Team is developing a new technology to convert sound signals into whalesong to camouflage military channels
A listening device picked up sound signals from 105km (65 miles) away at a depth of 200 metres (656 feet) during a field test in an important passageway for submarines, according to the study by the team at northwestern China.
The data transmission rate reached nearly 200 bits per second (bps), on par with the bandwidth of very low-frequency radio sent by a naval command to nuclear submarines using the world’s largest land-based antennas.
01:47
China’s world-first drone-carrier capable of operating on its own
Despite heavy noises in the background, the encrypted messages contained no mistakes, the researchers said.
Using commercially available technology, acoustic communication of this speed and quality is usually restricted to a distance of less than 10km.
In an experiment conducted by South Korean researchers last year using British hydrophones, for instance, a transmission rate of 128bps was recorded over a distance of 20km.
Low-frequency sound – such as calls made by whales – can travel for hundreds, or even thousands, of kilometres in the ocean, but identifying these signals and decoding meaningful information from them is difficult.