By John Keller
HUNTSVILLE, Ala. - Avionics computers based on the MIPS R3000 32-bit RISC microprocessor architecture form the foundation of a U.S. Army initiative to upgrade 242 AH-64A Apache attack helicopters to the improved AH-64D Longbow configuration.
Apache manufacturer McDonnell Douglas Helicopter of Mesa, Ariz., is awarding a $162 million contract to SCI Technology Government Division of Huntsville, Ala., to supply the main systems computers, weapons computers, and digital communications for the helicopter upgrade.
SCI engineers will provide four computers for each aircraft - two systems processors to control avionics, and two weapons processors to control target acquisition and weapons. The inter-communications system is a digital audio distribution system for crew members.
SCI designers base their systems and weapons computers for the Apache upgrade on the R3081E RISC central processor from Integrated Device Technology (IDT) Inc. of Santa Clara, Calif. The computers process 20 million instructions per second, have 16 megabytes of flash memory, four megabytes of static random access memory (SRAM), and 32 kilobytes of non-volatile SRAM.
SCI engineers are designing the flight computers to accommodate the IDT R4600 RISC microprocessor for future upgrades, says Dick Holloway, the SCI senior vice president and general manager.
The computers will have the SEM-E printed circuit card form factor and backplane data bus, and will connect to other aircraft systems via two 1 megabit- per-second MIL-STD 1553B serial data buses.
SCI`s computers, each of which weighs less than 14 pounds, also are to be part of 93 new AH-64D Longbow Apache helicopters for the United Kingdom and The Netherlands.
The first computer production delivery was set for last month, and is expected to increase to a production rate of 30 computers and six inter-communications systems each month.
The AH-64D, which can be equipped with or without advanced Longbow fire control radar, will have greater weapons accuracy at longer ranges than the AH-64A, and can operate more effectively at night and in bad weather. It uses laser, infrared, and other sensors to detect, classify, track and attack targets with its 16 laser- or radar-guided Hellfire missiles, 76 70 mm rockets, or a 30 mm automatic cannon.
Original plans for the Longbow Apache in 1989 specified SCI-built computers with dual 16-bit MIL-STD 1750A processors, but SCI designers, together with officials from the Army and McDonnell Douglas, decided in 1995 to move to a single R3000 RISC microprocessor in each computer because of the chip`s superior performance, says Steve Werner, SCI`s avionics department manager.
The R3000-based computer features one spare slot in its backplane "so we can put in another module to accommodate other interfaces," Warner says.
The AH-64D Longbow Apache attack helicopter will have R3000-based flight computers and MIL-STD 1553B data buses.
