By John McHale
Size, weight, and power (SWaP) requirements drive the designs of single-board computers (SBCs) for avionics systems. Defense and commercial avionics integrators want the fastest and hottest processors and SBCs on the market and at low power and low cost.
"For the most part, our customers are looking for the same thing they have always been looking for -- more I/O bandwidth, more processing bandwidth, and more functional density," says Rob Scidmore, president and chief executive officer of Extreme Engineering Solutions in Middleton, Wis. "Our customers are constantly requiring us to push the envelope with our embedded computing solutions."
"There's a trend toward better SWaP-enabled systems -- trying to do more processing in a smaller space," says Steve Edwards, chief technology officer, Curtiss-Wright Controls Embedded Computing in Leesburg, Va. "From an I/O perspective we see a lot of MIL-STD 1553 and some ARINC 429. We still see some interest in DO-178, but there are new challenges with getting DO-178 qualified on a multi-core processor."
"The solutions we are currently providing based on the multi-core processors from Freescale (QorIQ) and Intel (Intel Core i7 processor) are enabling us to deliver significant functional density, performance, and bandwidth upgrades to our customers," Scidmore says. "Now that four and eight core processors are finally hitting the street, I think our customers will need some time to really understand how to best utilize all of these cores for their application.
"We are also seeing requirements from our customers for more security capabilities such as data encryption, anti-tamper, secure erase, and declassification," Scidmore continues. "One other trend we are seeing is a requirement for smaller systems. We are currently satisfying this demand with 3U VPX and sub-1/2 ATR boxes, but there is pressure to go even smaller. I think in 2011 we will see a strong push within the VITA Standards Organization (VSO) to come up with a small form factor standard that the industry can support, as we did with VPX."
Curtiss-Wright officials also see VPX and small form factors as a wave of the future. "Many customers are migrating towards VPX platforms, especially on the 3U side since there are many 3U VPX SBCs available," Edwards says. "Also VPX will support high-speed signaling which is needed in some avionics applications."
Managing thermals still challenging
All the new processor technology brings performance benefits, but can also create headaches for SBC designers on how to get rid of the heat generated by the new chips.
"Thermal management is always a challenge but no more so today than it has been in the past," Scidmore says. "As the semiconductors get smaller, it makes heat transfer more difficult for us to deal with, but we manage to get the heat off of the boards. With the trend to multi-core processors, advancements in semiconductor manufacturing processes, and device integration, we continue to increase functional density, I/O bandwidth, and processor bandwidth and keep the thermals in the same ranges we have been dealing with for years."
"Avionics customers are challenged both by SWaP issues and also by new capability requirements," Edwards says. "Some customers upgrade legacy systems with new SBCs and are able to add some functionality at the same or lower overall system power by reducing the module count. However, since the SBCs are higher performance this leads to a higher power density (power/volume) and this becomes a thermal challenge. Other customers are not able to lower their module count so that end up with a higher system power as well and this can be a challenge for the integrators who have a fixed power budget to deal with."
There are demands from the integrators to meet "the 100-200 percent increase in performance mandate requirements without a hit to the chassis design to achieve the same thermal boundaries of the existing chassis in the current airframe," says Doug Patterson, vice president of business development at Aitech in Chatsworth, Calif. This is difficult to do and is typically handled on a case by case basis as many military and commercial avionics platforms will have different configurations, he adds.
"The thermal challenges get interesting when customers ask us to deliver conduction-cooled avionics systems with Freescale P4080 processors with eight cores or Intel Core i7 processors with four cores," Scidmore notes. "But in these situations, as long as we can make adjustments to at least one of the performance, size, and thermal constraints in a system, we can work within these constraints to come up with a workable solution for our customer."
Extreme's latest single-board computer is their XPedite7470, a 2nd generation Intel Core i7 processor-based 3U VPX SBC. "It represents the latest SBC technology for avionics applications," Scidmore says. The device has two PCI Express Fat Pipe P1 interconnects and two Gigabit Ethernet ports, according to the Extreme data sheet. It is targeted for high-bandwidth and processing intensive applications such as avionics and floating-point intensive applications such as radar, image processing, and signals intelligence.
Curtiss-Wright Controls Embedded Computing's latest avionics SBC is the VPX3-1256, also based on the new Intel Core i7-next-generation quad-core processor. The VPX3-1256 is designed for harsh-environment, air, and conduction-cooled aerospace, and defense applications. Each of the Core i7's four cores delivers 2.1 gigahertz of performance, according to a Curtiss Wright release.
GE Intelligent Platforms in Charlottesville, Va., is also offering a product based on the latest Intel processor. Their first product to be announced is the SBC624, a 6U OpenVPX SBC featuring a range of processor options including a quad core Intel Core i7 processor running as fast as 2.1 gigahertz, that is for applications such as signal processing in intelligence, surveillance, reconnaissance, radar, sonar. SBCs in 3U VPX, 6U VME, and 6U CompactPCI form factors will also be announced in the near future, together with a multiprocessor platform based on the new Intel processors.
Kontron in Eching, Germany announced that its first product based on the new Intel chip will be the Kontron COM Express basic ETXexpress-SC Computer-on-Module. Later this year a mini-ITX, Flex-ATX embedded motherboard and 6U CompactPCI blade will follow. Other platforms planned for 2011 include 3U CompactPCI, 3U VPX, AdvancedMC, PCIe/104, and ATX embedded motherboards.
Aitech offers the C110 rugged 6U VPX single-slot SBC with a Freescale MPC8640D processor and dual e600 Cores running at 1.25 gigahertz. The system is OpenVPX compliant, VITA 48 REDI compliant, and comes in conduction and air-cooled versions.