Navy's carriers go electronic
Navy's carriers go electronic
The service begins 20-year transition from mechanical to digital controls
The USS Ronald Reagan, which
By William Jackson
The nation's newest aircraft carrier, the USS Ronald Reagan, owes its integrated shipboard network to computer models and simulations.
The Navy Integrated Communications and Advanced Networks (ICAN) program is phasing out multiple standalone networks in favor of a single asynchronous transfer mode backbone to carry voice, data, navigational and mechanical control traffic, said engineer Kurt Clemente at Newport News Shipbuilding and Dry Dock Co. of Newport News, Va.
The Reagan, the last of the Navy's Nimitz-class carriers, is taking the first steps in a 20-year transition to a new class of all-electric carriers. They will eliminate mechanical control systems in favor of high-speed networks on what Rear Adm. William V. Cross II has called knowledge-centric ships.
'The ability to share information in a timely manner is critically important,' said Cross, the Navy's program executive officer for aircraft carriers. 'Carriers in the past have used mostly manual communications' via telephone and voice amplification that, though technically reliable, 'are manpower-intensive and conducive to errors.'Knowledge, not info
Network-centric warfare demands not just information but knowledge, Cross said, 'and that is where we believe the next big breakthrough will be.'
The Navy has established a timetable for the new carriers. The keel of the Reagan (CVN 76) was laid at Newport News last year, and the ship will be delivered to the Navy in 2002.
The as-yet-unnamed CVN 77X'X for experimental'is scheduled to be commissioned in 2008 as a transitional vessel for the new CVX class, which will have all-electronic combat systems. The first carrier of the all-electric class, CVX 1, will be commissioned in 2013. CVX 2, the full implementation, will follow in 2018.
Delivering knowledge rather than information means displaying a combat zone in real-time 3-D with identifiable graphical icons rather than radar blips or static diagrams. 'You can make better decisions with fewer hours of training and fewer people,' Cross said.
The Defense Department plans to install a prototype of such an Area Air Defense Commander module on the cruiser USS Shiloh this year.
Cross said the networks to support such modules will be mostly if not entirely cabled with fiber. They probably will use ATM switching and possibly wave division multiplexing and optical switching.
Optical switching 'is not too many years away,' he said, 'but it's probably beyond what we will be putting on the first of the new ships.'
An aircraft carrier is among the most complex ships afloat: 1,000 feet long and 17 stories high with a crew of 6,000, 3,000 of whom support the air wing. 'Everything a small city of 6,000 does, the ship does,' Cross said.
Shipboard networks are on the same scale. The Reagan will have almost 20 miles of fiber cable for an OC-12 ATM backbone connecting 16 nodes to the SmartSwitch 9500 chassis from Cabletron Systems Inc. of Rochester, N.H.
Clemente said each node can support hundreds of desktop drops to a mixture of client PCs served by Ethernet plus some ATM multimedia workstations. In addition, there will be some Fiber Distributed Data Interface circuits. Voice will travel by Integrated Services Digital Network links.
The Reagan's ICAN architecture was designed using OpNet Modeler from Mil3 Inc. of Washington. The model simulated system failures from fires and explosions. Tests showed that the network architecture could withstand two catastrophic failures in equipment node rooms without disrupting communications to other areas.
Network capacity was greater than originally thought, and the available bandwidth was hardly strained. Clemente said the main constraint was not bandwidth but multiple security levels and priorities.
Among the functions not integrated on the ship's network are classified traffic and video, which travel over coaxial cable, plus much of the machinery control.Steam disappears
The new carrier class will not need machinery control systems. Pneumatic and hydraulic systems will be replaced by electrical systems, and even steam-powered aircraft catapults will give way to electromagnetic ones. Everything but propulsion will be electric to ease electronic control.
Although shipboard complements will shrink, the electrical generation requirements will be massive. The Reagan will have a generating capacity of 32 megawatts. The CVX 1 will generate 104 megawatts from four steam-powered turbo generators, each with 26-megawatt capacity.
The advanced hardware, though costly, will operate with smaller crews, which Cross called 'our greatest cost now.'x