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Satellite meets sonar, links submarines to real world

Previously, submarines could not be reached when they were deep underwater on operations. A new integrated satellite sonar system will allow submarines to be contacted by commanders all over the world, regardless of their location.

Previously, submarines were unreachable when they were deep underwater on operations. Now, a new integrated satellite sonar system will allow submarines to be contacted by commanders all over the world, regardless of their location.

The system, developed by defence manufacturer Raytheon, will be adopted by the US Navy following the signing of a US$5.2 million contract between the two.

According to Raytheon, current submarine communications protocols are the same now as they were 60 years ago. In order to communicate, submarines either initiate contact with commanders by transmitting or stick to set schedules for sending and receiving information. This introduces delays into operations and limits a submarine's ability to participate across the full range of naval missions, said Raytheon.

Raytheon's Deep Siren will enable "a commander anywhere in the world to contact a submarine immediately, no matter its speed or depth", Integrated Communications Systems VP Jerry Powlen said in a statement.

The system works by sending communications to the submarine via satellite to expendable acoustic buoys, which translate the satellite message into an acoustic signal. The signal is then transmitted throughout the submarine's area of operations.

The submarine receives the signal using installed sonar equipment and a receiving station, most likely a laptop, interfaces with sonar equipment to translate the signal back to text, to be read by a member of the crew.

The number of buoys used will "likely be dependent upon the nature and intensity of operations", a Raytheon spokesperson told ZDNet Australia. Their range of acoustic communications depends on water conditions, with shorter ranges achievable in shallow water (less than 200m) than in deeper water (1500m), the relative ranges being around 30 miles and 150 miles respectively.

The buoys will be affected by drift, the spokesperson said, which can move them out of the field of operations. However, the buoys report their position periodically to the submarine or other vessels so that another buoy can be deployed by either party if the in-service buoy is carried out of range.

The spokesperson said that a number of technological and engineering advances which have occurred over the last decade -- including increased computer processing power and miniaturisation of satellite communications hardware -- have been fitted together to produce the communications system.