Navy develops two-way radio communication for submerged submarines

System provides first-time ability to fully integrate vessels under water into strike group operations.

The Navy has developed systems using floating radio antennas and buoys that will provide submerged submarines with two-way communications for the first time in history, a top official at the Space and Naval Warfare Systems Center said at a news briefing on Tuesday.

Until now, submarines had to be at periscope depth with masts above the water to handle two-way radio communications. While submerged they could receive but not send radio messages over low-frequency networks.

SPAWAR's Communications Speed and Depth program will use floating antennas to provide two-way communications to submerged submarines over high-frequency radio systems adapted to handle Internet protocol traffic as well as floating buoys to communicate with military and commercial satellites, said Capt. Dean Richter, program executive officer for the Command, Control, Communications, Computers and Intelligence's submarine integration program.

Richter said the Navy completed an operational test of the High Frequency Internet protocol system in December 2007, allowing the USS Montpelier attack submarine to exchange two-way message traffic with eight ships in the USS Harry S. Truman carrier strike group at a date rate of 9.6Kps.

Even at roughly one-fifth the speed of a standard 56Kps dial-up modem, the system allowed the submarine to be fully integrated into strike group operations and Navy networks to share situational awareness, plan collaboratively and execute missions with joint forces, Richter said.

SPAWAR also has developed floating buoys that connect to submerged submarines by fiber-optic cables to provide two-way satellite communications, he said. The buoys can exchange data with the commercial Iridium satellite system at a rate of 2.4Kpb and with military ultra-high frequency satellite systems at 32Kpbs, soon to be boosted to 64Kpbs, according to Richter.

The system, to be installed on surface ships and submarines as part of the Navy's Automated Digital Network System, operates at or near line-of-sight distances, Richter said, using modems from Harris Corp. and routers from Cisco Systems Inc.

The Navy plans to install the High Frequency Internet protocol and buoy systems on attack and guided missile submarines. Ballistic missile submarines will be equipped with buoy systems, and all 73 boats in the fleet will get two-way communications in one form or the other, Richter said. The program is fully funded with installations to continue through 2015, he said.

SPAWAR also has Sea Deep, a project to equip manned and unmanned aircraft with lasers to penetrate the ocean depths and beam high bandwidth information to submerged submarines. Sea Deep can transmit data at 1Mpbs, Richter said, and he views it as the holy grail of submerged submarine communications. SPAWAR plans to demonstrate Sea Deep in an exercise later this year, he said, but added that the program is not funded.