Underwater wireless communication is not a new concept, but until recently, it was nothing more than pings, dots and dashes, that only a trained ear could decipher.
Acoustic modems now are making it possible to transfer real-time data and e-mail from submarines, oil pipelines, research stations and other underwater vessels. Recent tests conducted by the U.S. Navy also revealed these tasks could be performed without its submarines being detected.
Using an ATM 885 Telesonar Acoustic Modem from Benthos Inc., a manufacturer and supplier of oceanographic products, the Navy submarine USS Dolphin, while cruising at a depth of 400 feet, was able to successfully send several e-mail messages via the Internet to facilities located on shore.
“Sending digital data underwater is nothing more than broadcasting a series of tones that are representative of the data you want to send. The modem is the size of a tennis ball can and it broadcasts those bytes,” said John L. Coughlin, president and chief executive officer of Benthos.
Acoustic modems send digital data underwater using sound energy because normal electromagnetic waves will not penetrate water, Benthos said. The e-mail messages sent by the Dolphin were received by repeater buoys, which transferred the messages to the shore and then to the Internet.
Benthos said the Dolphin also communicated with other submerged modems, demonstrating the ability to communicate with and control various underwater devices.
“Shooting data horizontally is difficult, but it can be configured in a network to provide extended data communications capability,” Coughlin said.
Coughlin noted that in order to achieve maximum effectiveness, the repeater buoys need to be within three or four miles of the modem, and the buoys need to be within seven or eight miles of the shore. Benthos’ current acoustic modem sends data at rates of 2600 baud, or 9,600 bits per second. Coughlin said a 9600 baud modem will be out later this year.
As a result of the recent tests with the Dolphin and Benthos’ acoustic modem, the Navy hopes to eventually have integrated subsea wireless communication, including manned and unmanned vehicles, sensors, swimmer delivery systems and weapons systems, among others applications, said Coughlin.
Commercial applications of underwater wireless communication include oil companies equipping pipes with corrosion monitoring equipment that can telemeter information back to the surface, and organizations such as the National Oceanographic and Atmospheric Administration using them to send and receive scientific data to aid research studies and predict weather phenomena.
