By John Keller
MANASSAS, Va. - Combat systems designers are seeking to use purely commercial-grade components in an upgrade of U.S. Los Angeles-class (SSN-688) attack submarines by concentrating on shock-isolation techniques and ruggedized enclosures.
"We are taking ruggedization to the structural level so we can use full-commercial cards," says Skip Price, senior hardware engineer in the Navy Systems Group of Lockheed Martin Federal Systems in Manassas, Va. "We are doing special things at the cabinet level for shock, vibration, heat dissipation, and cooling."
Lockheed Martin Federal is prime contractor for the U.S. Navy`s Acoustic Rapid COTS Insertion (ARCI) initiative to replace as much military-grade electronic hardware as possible with commercial off-the-shelf (COTS) technology in the AN/BSY-1 and AN/BQQ-5 combat systems aboard 688-class boats.
ARCI technology is also expected to influence designs of the Navy`s future New Attack Submarine, as well as upgrades to the AN/BQQ-6 sonar signal processing systems aboard U.S. Navy Ohio-class (SSBN-726) ballistic missile submarines.
Cost is the chief motivation behind using commercial-grade components, Price explains. "We don`t want to get into rugged components because you lose all your cost advantage that way," he says. "It`s cheap to build a rugged enclosure to allow you to use these commercial products. That`s the tack we have taken on this program."
The ARCI 6U VME-based architecture derives its processing power from the Multi-Purpose Processor (MPP) from Digital Systems Resources of Fairfax, Va. MPP is based on the 21060 SHARC digital signal processor from Analog Devices of Norwood, Mass., and the Raceway multiprocessor interconnect from Mercury Computer Systems Inc. of Chelmsford, Mass.
ARCI, which began in early 1996, calls for three delivery phases through the end of 1991, Price explains. The first delivery - a towed array sonar with COTS components - will be in November 1997. The second - adding COTS components to the hull-mounted sonar - will be in December 1996, while the third phase - using COTS signal processing on the submarine bow-mounted spherical sonar array - will be in December 1999.
During the first two phases of delivery, naval officials will operate the new COTS sonar-processing hardware in parallel with the older military-grade equipment, Price says. The last phase will involve removing all the military-grade equipment and using only the new COTS gear.
In one example of the ARCI design approach, Price says his engineers are using a 2604 PowerPC VME single-board computer from the Motorola Inc. Computer Group in Tempe, Ariz., as the slot-one controller for the entire ARCI VME chassis.
Although the 2604 has one slot for a PCI Mezzanine Card (PMC), the ARCI design calls for more I/O. To address the problem, designers are using the RM901 PMC expansion board from RAMix Inc. of Chatsworth, Calif. "We are attaching the RAMix board physically to this Motorola PowerPC card, and it gives us two additional PMC slots for more functionality," Price says.
Designers will use one PMC slot for a Fiber Distributed Data Interface high-speed data bus interconnect, and the other for additional flash memory for operating system and application software, Price says. "RAMix is the only card vendor that is making an attachment card to this Motorola card," he says. The ARCI operating system is VX Works from Wind River Systems in Alameda, Calif.
The flash PMC, also from RAMix, has a COTS PCMCIA flash memory card attached. This setup streamlines program loading. "Typically what you would do in a VME environment is go out across Ethernet to a workstation or disk drive somewhere and pull in your operating system and application files," Price says. "It is a very slow and tedious way to do that. We wanted a local source to contain this data."
The RAMix card Lockheed Martin engineers are using has a 40-megabyte PCMCIA flash card, which they can easily upgrade to 170 megabytes or more when the system needs it, Price says.
The RM901 PMC expansion board from RAMix Inc. (right) adds I/O capability for the Acoustic Rapid COTS Insertion program for Los Angeles-class attack submarines such as the USS Philadelphia, pictured above.
