Military Embedded Systems

From 6U to 3U: Expand into new markets by leveraging existing hardware/software IP


August 15, 2014

Jacob Sealander


An industry perspective from Curtiss-Wright Defense Solutions

For defense and aerospace prime contractors, recent changes in budgets and mission strategy have helped to make smaller platforms an increasingly attractive opportunity for growing their business, both domestically and in international markets where size, weight, power and cost (SWaP-C) constraints are major drivers. Many emerging smaller platforms require similar application and processing functionality to that found on larger aircraft and ground vehicles, but are constrained by available space and smaller budgets. One main difference is that these platforms’ smaller size often results in reduced capabilities because of fewer sensors or subsystems onboard. These smaller platforms are showing up in many areas, particularly in international markets.

In response to these emerging market opportunities, system integrators have attempted to interest customers in existing 6U architecture-based system solutions designed for larger platforms, or have proposed designing new smaller 3U solutions from the ground up. A better, more innovative approach is to transition the larger system’s existing software application from its original 6U design into a smaller 3U architecture, by reducing – or “de-featuring” the application, where appropriate, to better match the target smaller platform and/or the new market’s budget limitations.

In this approach, the existing 6U-based application software, or Operational Flight Program (OFP), is viewed as a superset of functionality. Because the smaller platform is more SWaP-C sensitive, transitioning a subset of the application’s functionality onto the new 3U system satisfies the more intense SWaP-C constraints while preserving the system integrator’s investment in IP and software development (the prime contractor’s differentiating “secret sauce”). The original 6U hardware can be easily transitioned into a smaller, more cost-effective 3U architecture as long as the processor and memory architecture remain consistent. This enables the system integrator to leverage valuable IP and software that resides on the hardware platform, regardless if it is 6U or 3U based.

What makes this approach so powerful is the availability of 3U processing modules that provide true commonality with the earlier, more fully-featured 6U boards upon which today’s deployed systems are typically based (taking into account the five-10 year lifecycle required to deploy large military systems on large airborne and ground platforms). Many 6U products that were developed 10 years ago are today only a couple of years into volume production. However, 10 years ago a 3U approach wasn’t viable due to the density of I/O or processing capability then available. With advances in chip technology, it’s now possible to fit 100 percent of the functionality of an older 6U card onto a 3U card because the equivalent processing and memory devices require a lot less board real estate. The trade-off in moving from 6U to 3U will most often be a reduction in the number of I/O channels and interfaces, but not in the type of I/O. Also, today’s 3U boards typically provide PMC/XMC mezzanine expansion to support unique I/O requirements.

The key to this approach is for system integrators to work with commercial off-the-shelf (COTS) vendors to identify those features that can be removed to make the 3U system best fit the new target platform. The original software and hardware feature set can be selectively reduced, resulting in a new class of smaller, cost-effective product offerings designed to hit the sweet spot for smaller SWaP-C sensitive platforms, such as unmanned aerial vehicles (UAVs) and lightweight ground vehicles that can be well addressed with 3U solutions.

Today, leading COTS board vendors offer 3U board equivalents to earlier 6U offerings. They feature the same processor, memory, memory bus, and components as the 6U board. In many cases the BSP developed for the original system’s VME single board computers (SBCs) will also run on its 3U VPX equivalent. This means that a prime contractor can approach an adjacent market with a smaller, less costly (typically 25-50 percent less expensive) 3U equivalent of their existing large solutions, enabling them to leverage their full software/hardware IP value. In fact, every 6U VME and VPX SBC that Curtiss-Wright has developed has a 3U equivalent design.

An example can be seen in a comparison of the Freescale QorIQ P4080-based 6U VME-186 SBC to the 3U VPX3-131, where both boards feature the same P4080 processor. Each delivers the exact same core FPGA functions such as Boot PROM, NOR Flash, VRAM, and health monitoring. Both boards provide the same amount of memory and the same memory bus. The main difference between both boards is the I/O complement. Instead of the two PMC/XMC sites on the 6U VME SBC, the 3U VPX card provides a single PMC/XMC site. Instead of the three GbE ports on the VME SBC, there are two ports on the 3U VPX equivalent, and instead of four RS-232 serial channels, the 3U board provides two. While the 6U card offers I/O flexibility via the use of IPM modules, the 3U card is limited to the I/O on the card or expansion via the PMC/XMC mezzanine site.

These I/O limitations, instead of being detrimental, result in a much better fit for the new class of smaller, less costly platforms. The “subset approach” provides system integrators with a way to leverage the full potential of their existing application into new market opportunities. The first step is to identify the 3U alternative to their current 6U system using their COTS vendor’s range of MIL-qualified 3U SBC, DSP, FPGA, and GPGPU modules.

Jacob Sealander Chief Architect, Integrated Systems Curtiss-Wright Defense Solutions


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