UAV Airframes and Missions Drive Embedded Computing Choices

Every branch of the armed forces has a need for capabilities delivered from unmanned aerial vehicle/ unmanned aerial system (UAV/UAS) platforms. These unmanned vehicles have proved critical to improving situational awareness with surveillance and data collection, real-time communications, and even armament deployment. Key to the military’s technological approach to a modernized battlefield, new ideas for UAS use and deployment are spurring their expanded development as a priority among the Joint Forces. Enhanced systems are required to enable more sophisticated functionality, weaponization, and longer flight time at greater altitudes. Systems also need to be versatile to support a broader size range of UAS/UAV vehicles, from tanker-sized vehicles all the way down to micro-sized equipment. These diverse requirements are certainly a challenge to designers who must also ensure high reliability when operating in the rugged environment of a battlefield.

According to a recent U.S. Armed Forces report, “Standards and interoperability are keys to the Joint Forces gaining information superiority in today’s network enabled environment.” As a result, UAV development goals mandate a common set of airframes. Each UAV platform needs to be tailored to support one or more of the Joint Forces’ priorities that are based on a family of systems using standard interfaces and interoperable “plug-and-play” payloads.

This mandate for interoperability means that military embedded designers must take an open-architecture, commercial off-the-shelf (COTS) form factor approach that will allow them to focus on meeting UAV platform objectives while integrating the system with the Joint Forces’ worldwide information network. Consider in turn, the range of airframes such as Predator, Global Hawk, Fire Scout, Raven, and many others; their accompanying ground command and control systems; and ultimately, their role in keeping soldiers safe and sharing critical information. To deliver on this promise, designers must develop a deep understanding of their options for high-bandwidth, high-performance, standards-based systems that not only handle compute-intensive applications, but also deliver essential upgradability and interoperability.

Embedded Computing Form Factor Options

Implementing a truly form-factor-independent approach requires that military system designers understand the advantages and tradeoffs of any number of embedded computing form factors. Today’s broad range of standards-based form factors include Computer-on-Modules (COMs), VPX, MicroTCA, CompactPCI, and AdvancedTCA, and each delivers specific features that need to be weighed against the requirements of the airframe and its mission.

As an example, space-constrained applications that require high performance may be ideal for COMs-based solutions. The design, however, must be able to handle a two-board solution, allowing for customization through the module’s accompanying carrier board. MicroTCA provides a ruggedized solution with high-bandwidth performance that is well suited to ground control systems processing data nonstop. Leveraged from the ANSI/VITA 47 specification that defines operation in these types of environmental conditions, standards-based MicroTCA provides multiple options that include rugged air-cooled MicroTCA (MTCA.1), hardened MicroTCA (MTCA.2), and conduction-cooled MicroTCA (MTCA.3).

In contrast, the VPX form factor has been designed for ruggedness from the ground up. Applications that demand serial switched fabrics and high-speed signal processing in extreme physical environments are well supported by VPX. For example, VME-based airborne and ground control systems fielded years ago are being upgraded to VPX in order to keep up with today’s data-centric application requirements, and VPX’s compatibility is further extending VME’s already deeply established presence on the military embedded landscape.

Power and Performance Advancements

SWaP is king, and UAV payloads such as video, radar, EO/IR, and ECM challenge designers to balance performance and SWaP issues. These payloads demand higher-performance processing for differential signal processing. Intel’s 32-nm processor technology appeals here because it reduces the power envelope while providing enhanced lifecycle, extended temperature operations, and overall performance. Benchmark tests have shown the 32-nm core architecture meets and exceeds the performance once relegated to other processor technologies as a result of improvements in vector processing capabilities, performance per watt, lower power consumption, and heat dissipation.

Core i7-based form factors include a more efficient two-chip solution, delivering better signal integrity and minimized board space. This enables higher performance for smaller, power-hungry portable designs. It also brings significantly enhanced integrated graphics capabilities and data flow performance via the integrated Intel QM57 Express chipset and advanced display interfaces, which is a significant breakthrough for compute and graphics intensive imaging or surveillance UAV/UAS applications. In addition, applications can now support multiple graphical and multimedia functions including separate ports for SDVO and PEG. An integrated ECC memory controller matches high data integrity requirements, and additional I/O and PCIExpress configuration options optimize flexibility for both airborne and ground system design.

Airframes Dictate Systems and Platform Selection

The broad range of airframes and application objectives for UAS/UAVs best illustrates selected design strengths (i.e., high bandwidth) and the mandate for platform-independent design. The specific mission for short, medium, or long-range UAVs may vary considerably; however, improved situational awareness is the overarching goal.

Larger airframes such as RQ-4 Global Hawk may rely on VPX to deliver next-generation radar and full-motion video capabilities. Compressed, live video or other information is routinely downloaded to portable devices on the ground that demand increased image compression and bandwidth. VPX offers high-frequency processing as well as a reliable fabric solution, ideal for these data-intensive UAV applications. The VPX form factor and architecture enable higher-performance processing per slot and also higher-speed interconnects between processing and I/O elements using PCIe, 10GbE, or sRIO. These interconnects provide 10 Gb/s between elements or several hundred GB/s in aggregate, depending on the system implementation.

Another advantage of VPX is that it can be integrated with CODECS such as ITU-T H.263, H.264 (MPEG-4 part 10), and JPEG2000 to provide very efficient image compression. VPX is also supported by rugged integrated systems development. COTS systems such as the conduction-cooled, half-short ATR chassis are designed for long-term UAV programs, support the VPX form factor, and meet the MIL-E-5400 standard to withstand extremes of temperature, vibration, shock, salt spray, sand, and chemical exposure while maintaining a sealed environment.

Midrange airframes are characterized by the MQ-1 Predator and MQ-9 Reaper. Predator is an armed, multi-role, long-endurance UAS, carrying payloads such as EO/IR, laser target marker, laser illuminator, and signal intelligence. Used primarily for persistent ISR (intelligence, surveillance, reconnaissance) functions, Predator and its crew can quickly adjust to handle close air support, combat search and rescue support, precision strike, buddy laze, convoy overwatch, raid overwatch, target development, and terminal air control.

Two datalink options allow Predator to be flown line-of-sight within approximately 100 miles of the launch and recovery base, or flown beyond line-of-sight via satellite datalinks. Manual flying, semi-autonomous monitored flight, and pre-programmed flight systems demand rugged, high bandwidth, and present a good example of a MicroTCA implementation as an alternative to VPX. MTCA.3, the PICMG standard for conduction-cooled MicroTCA, offers a slightly smaller form factor than VPX with similar high-speed connectivity, making it ideally suited for these types of applications.

Smaller airframes such as the Wasp III, RQ-11 Raven, and the Scan Eagle, have perhaps grown the most in terms of their usefulness. Today, this group of small, motorized, or even hand-launched devices is viewed as highly effective in supporting integrated manned and unmanned mission sets beyond the specific capabilities of the MQ1/9 and RQ-4, including modular payloads such as electro-optical cameras and infrared imagers with persistent stare capability and small-vehicle resolution from up to five miles away. Embedded advancements in power storage, motor design, miniaturization, and design and optimization techniques have led to the continuing evolution of this airframe category, programmed with GPS-based autonomous navigation, to perform day or night surveillance and reconnaissance missions at low altitude. Extended temperature COMs are not only improving SWaP considerations for these high-performance vehicles, enhancing imaging resolution and handling mission-critical communications and network throughput, but also positioning these small-form-factor designs for long-term upgradability and interoperability within the Joint Forces.

Long-Term Military Value

The value of any UAS airframe expands dramatically with ever-increasing payload capabilities, particularly in the area of situational awareness and higher-performance radar and surveillance systems. Since all UAS platforms must deal with disadvantaged datalinks, the military is making significant investments in sensor technology, datalinks, and ground stations to support new requirements in the coming years. For example, the U.S. Joint Forces have recently invested in systems to support wide-area surveillance on the MQ-9 platform “to provide up to 50 video streams per sensor within a few years.”

As a result of their expanded mission objectives, there are significant pressures on embedded computing form factors to meet imagery payload requirements in terms of not only the number and bandwidth of the links, but their higher resolution and coding requirements. Each aircraft platform is now expected to host multiple payloads, so bandwidth availability and real-time processing must also support enhanced compression, equalization, and digital filtering. From a designer’s perspective, the diversity of UAV/UAS applications requires a thorough evaluation of embedded form factors, processing technologies, and platforms to determine the optimal solution to help them successfully address mission needs and provide modular, network-centric value.

This article was written by David French, Director of Military and Aerospace Business Development at Kontron, Poway, CA. For more information, Click Here .