Military aircraft avionics face new data-processing and security demands

A few trends are emerging in military aircraft avionics – including a continued push toward large touch-screen displays, as well as a migration to multicore processing, open architectures, and a new focus on improving cyber resilience.

Open architecture designs are a standard requirement these days for military aircraft platforms undergoing avionics upgrades and tech refreshes to their flight systems. Open architecture design is needed in all platforms, from aging craft like as the C-130 or F-16 all the way up to the 5th-generation fighters like the F-35. From the display to the processor to the moving map, open architecture designs that embrace common standards have become the rule rather than the exception.

The F-35’s latest tech refresh program is a perfect example of the open architecture approach.

“The key to winning the F-35 avionics contract was our open systems architecture approach,” says Bryant Henson, vice president and general manager for Harris Corporation’s Electronic Systems Avionics Business Unit (Melbourne, Florida). “We’ve embraced open systems architectures at Harris, and our next-gen Integrated Core Processor (ICP) is a perfect example of that. We standardized the interfaces, components, and cards for the computer. We also purposely made the ICP processor-­ card -agnostic, so that future refreshes aren’t locked into one provider and we can easily and cost-effectively upgrade the computer, chassis, or the processor. That’s how we’re driving capability while reducing size, weight, power (SWaP), and cost.

“We are aggressively pursuing cost reduction across the F-35 enterprise and, after conducting a thorough review and robust competition, we’re confident the next generation [ICP] will reduce costs and deliver transformational capabilities for the war­fighter,” says Greg Ulmer, Lockheed Martin vice president and general manager of the F-35 program in a Lockheed Martin release. The ICP “ will have positive benefits for all customers in terms of life cycle cost, capability, reliability, and more,” he adds.

Harris “also invested heavily in high-density electronic packaging for the cards and efficient thermal-management techniques – specifically a liquid-cooled chassis that houses the ICP and an air-cooled solution for the panoramic cockpit display,” Henson adds.

Open architectures will make tech refreshes on the F-35 and other platforms much more efficient down the road.

Harris has increased its content on the F-35 through a Technology Refresh 3 (TR3) modernization effort by providing – in addition to the ICP – the advanced memory system and the electronics behind the panoramic cockpit display, he continues. “The ICP essentially acts as the brains of the F-35 –processing data for the aircraft’s communications, sensors, electronic warfare, guidance and control, as well as cockpit and helmet displays. The computer operating the display also functions as the backup computer for the aircraft.” (Figure 1.)

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Figure 1: The Panoramic Cockpit Display (PCD) Electronic Unit from Harris Corporation controls the PCD and also functions as the backup computer for the aircraft. Photo courtesy of Harris Corporation.
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“For the F-35 avionics program, we’re providing more than 1,700 different components, including network-interfaced units, power supplies, integrated chassis that support communication, navigation, computer processing, and a multifunction advanced data link that enables the aircraft to communicate covertly,” Henson says. Thanks to the open architecture approach, Henson says the next-gen ICP system is targeted to generate a 75 percent reduction in unit cost compared to the current system, as well as a 25-time increase in computing power to support planned capability enhancements, greater software stability, higher reliability, and increased diagnostics that result in lower sustainment costs.

Open architecture initiatives

A key force behind open architecture developments in avionics has been the Future Airborne Capability Environment (FACE) Consortium, an aviation-focused group comprised of industry suppliers, customers, and users working to create an open architecture, standards, and business model geared toward helping speed new capabilities to warfighters faster. All three services – Air Force, Army, and Navy – are also involved.

As an open avionics standard, FACE makes military computing operations more robust, interoperable, portable, and secure. It’s designed to enable developers to create and deploy a wide catalog of applications for use across the entire spectrum of military aviation systems through a common operating environment.

Software is playing “an increasing role, which generally represents the most complex part of development programs,” says Marc Ayala, director of Fixed Wing Business Development for Collins Aerospace (Cedar Rapids, Iowa). “In the old days, if you wanted a new capability added to your aircraft, it usually meant the addition of a new box. Today, many capabilities can be added by adjusting software without any hardware changes.”

Open systems standards such as FACE and others “are causing many within the industry to rethink investments and business models on the military market,” he adds. “As an example, Collins Aerospace recently debuted a software-based FACE-compliant flight management system that can be loaded and run on any conforming processor. It wouldn’t have been possible without the common interfaces established by FACE.”

At Harris “we are designing our avionics software systems to be aligned with HOST [Hardware Open Systems Technologies] and FACE with a foundation based on FACE, while not exactly compliant to FACE at this time,” Henson says. “One area that is conformant to FACE is the FliteScene digital moving map used by the Army, Navy, Marine Corps, Air Force, and Coast Guard on a variety of rotary aircraft. Regarding FACE, we’re an active participant in FACE and continue to bring ideas back to the committees.

The Sensor Open Systems Architecture (SOSA) Consortium is working to create open system reference architectures applicable to military and commercial sensor systems. These architectures use modular design and widely supported, consensus-based nonproprietary standards for key interfaces.

“Regarding SOSA, our electronic warfare business is following it closely, but we go to market as a corporation and look at ways to leverage our business investment across our business units – including avionics, electronic warfare, and others,” explains Henson. “We’re adding multifunctionality to every design as we reduce SWaP and increase performance through investments across multiple domains. The open architecture approaches and concepts that come out of SOSA, FACE, and other initiatives enable multifunctionality, and we leverage them across Harris regardless of application.”

Harris tries to push multifunctionality into every solution it designs because “reducing SWaP is a high priority for every aircraft platform,” explains Henson. “By adding multifunctionality in the smaller electronic footprint, you enable not only easier upgrades but more efficient integration of new capabilities such as better anti-jam technology. Open architectures make all of this possible and affordable in the long term.”

It also makes it easier, Henson notes, to solve future problems and deploy the technology to warfighters faster. “One example is improving protected communications, because that’s what wins the game – resilience and protected communications,” he says.

Security in flight systems

An emerging trend is a focus on security. “While not always a requirement in programs, we’ve made security an important part of our open systems architectures at Harris,” says Henson. “We started to standardize on these interfaces, using COTS [commercial off-the-shelf] technology and spending the time to overcome the challenge through high-speed cryptography. We’ve also invested in multi-level security – MILS [multiple independent levels of security] and MLS [multilevel security]. Some customers have specific security requirements but, in general, we look at where the marketplace is going with our crypto solutions based on a certified architecture.”

Many military aircraft avionics systems rely on COTS components today, primarily for cost savings and convenience. But is a shift away from COTS likely to ensure that parts are made in the U.S. because of security concerns? Maybe.

“In certain markets, such as a commercial-derivative aircraft where civil certification is a requirement, COTS is a perfect fit,” Ayala says. “For other more specialized missions, COTS products serve as a baseline to start from. Due to mission requirements, COTS products are often tweaked to meet the mission but, by doing so, our customers see a dramatic reduction in development and integration cost. As processing huge amounts of sensor data and cyberdefense programs running in the background become more prevalent, we may see a departure from the traditional COTS model into more of a military off-the-shelf (MOTS) model where manufacturers carry two different product lines – one for commercial and one for military.”

Trends in avionics displays

On the avionics display front, the primary trends are, not surprisingly, still “large format and touch screen,” Ayala says. “Many flight decks are migrating to three or four large displays, and pilots are becoming increasingly familiar with touch screen as the human machine interface.”

A secondary trend, Ayala adds, is the analysis of large amounts of data driving migration to multicore. Processing demands and cyber resilience are next in driving inclusion of multicore processors: “Certification of multicore processors in avionics will be something every integrator will deal with.”

“The military isn’t required to abide by FAA safety certification standards such as DO-178C [Software Considerations in Airborne Systems and Equipment] or DO-254 [Design Assurance Guidance for Airborne Electronic Hardware], but we need to provide a path to compliance if a customer chooses to certify to it,” Harris’s Henson says. “At that point, it’s a matter of being resolved at the design and testing level.”

One primary difference between military and civilian aircraft avionics “is the qualification to more stringent military environmental standards such as sand, extreme temperatures, EMI, and salt fog,” Ayala points out. “A secondary effect surrounds the addition of specialized mission functions such as weapons targeting and surveillance sensors.”

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