VNX for Defence: Compact, Power-Efficient, and Future-Proof

Modern defense and aerospace systems face an increasingly complex challenge: delivering high-performance computing capabilities while meeting stringent size, weight, and power (SWaP) constraints. Traditional solutions like OpenVPX excel in high-performance applications but can be too large and power-hungry for emerging platforms such as unmanned vehicles, portable military equipment, and space-constrained systems.

To address this gap, VITA ratified the VNX standard in 2017, extending the proven modularity of OpenVPX into a smaller yet powerful format. VNX defines a small-format, modular system architecture for embedded computing systems and is specifically designed for applications where compact dimensions, low weight, and low power consumption are critical. Key areas of use include unmanned vehicles, portable electronic devices, and robotic controllers, where these SWaP constraints are essential for mission success.

VNX and VNX+ as next-generation standards

VNX, as defined in VITA 74, provides mechanical and electrical boundaries while following OpenVPX design principles. A VNX module is 4.5 times smaller than a comparable 3U OpenVPX module, significantly lighter, and easily integrated into tight spaces.

The VNX standard defines two plug-in module sizes: 12.5 mm and 19 mm. Unlike OpenVPX, there is no specifically defined backplane, but VNX offers a 4-slot reference backplane to simplify implementation for developers. The standard also describes example enclosure sizes as starting points for development.

In addition to VNX, VITA introduced the VNX+ standard (VITA 90) in 2018 to meet growing demands for performance, modularity, and interface diversity in SWaP-critical applications such as UAVs, missiles, and portable systems. Compared to the original VNX and PC/104, VNX+ offers higher electrical performance. Specifically, it supports PCIe Gen4, Ethernet up to 100G, and expanded I/O capacity through a more capable backplane interface and improved cooling options. This bridges the gap between ultra-compact systems and high-performance OpenVPX platforms for modern defence and aerospace systems while ensuring long-term availability.

VNX vs. PC104 and OpenVPX

To understand the significance of VNX and VNX+, it’s useful to compare these standards with the OpenVPX and PC/104. Each standard has its own strengths and is suitable for different applications.

Figure 1: The VF370 is a 3U OpenVPX module, fully designed, manufactured, and qualified to MIL-STD 810 G (CN1) and RTCA/DO160G certifications. (Figure: Sundance)

 

Feature OpenVPX VNX PC104
Size 3U VPX: 100 mm x 170 mm VNX: 100 mm x 72 mm PC104: 90 mm x 96 mm
Weight Heavier Very lightweight Lightweight
Power Consumption Higher Very low Lower
Modularity Backplane-based architecture with multiple slots Also supports backplane-based design, allowing flexible module integration 6–8 modules can be stacked, without defining a backplane
Connectivity Supports PCIe, Ethernet, USB, Serial RapidIO Supports the same interfaces but in a more compact form Supports ISA, PCIe, USB, SATA, Ethernet, Serial IO
Cooling Conduction-cooled and air-cooled options Conduction-cooled and air-cooled designs Passive or air cooling, also conduction cooling

Table 1: Features of VNX in comparison with PC104 and OpenVPX.

VNX (VITA 74) offers the best balance for SWaP-critical applications thanks to its ultra-compact size, vibration resistance, and energy efficiency—ideal for mobile platforms like UAVs and portable systems. In comparison, OpenVPX provides significantly more computing power and I/O capacity, but at the cost of higher size, power, and cooling demands, making it better suited for larger aerospace or defence systems. PC/104 lies somewhere in between: compact and well-established but technologically limited in bandwidth and modularity compared to VNX or OpenVPX.

Figure 2: The EMC²-SoM3-100 is a PCIe/104 OneBank™ SBC with a PolarFire FPGA and a VITA57.1 FMC™ LPC I/O board, and the Sundance SEIC expansion connector. (Figure: Sundance)

Expand future defence applications with VNX

While OpenVPX is designed for high-performance, scalable systems requiring powerful computing and modularity, VNX offers a compact, SWaP-optimised solution for size-, weight-, and power-constrained applications. As such, VNX is an excellent fit for a range of defence applications, including:

  • Unmanned systems: UAVs, UGVs, and USVs (drones, autonomous robots, and watercraft)
  • Portable military equipment: Mobile communication systems, sensor platforms, C4ISR devices
  • Space applications: CubeSats, satellites, spacecraft
  • Portable surveillance sensors: SIGINT devices, miniaturised monitoring sensors

Sundance/Etion Create’s roadmap and future design considerations

Sundance and Etion Create are working together to develop forward-looking solutions based on the VNX standard while continuing to evolve the capabilities of OpenVPX and VPX systems. One highlight is the VNX+ to 3U VPX adapter, which enables VNX+ plug-in modules to be integrated into VPX slot profiles. This allows developers to migrate from VPX to VNX without replacing the entire peripheral ecosystem. The adapter functions passively, without interfering with the components of the VNX module.

Figure 3: Modular VNX+ VITA 90 standard. (Figure: Sundance)

In addition, Elma Electronic recently introduced the FlexVNX+ portable development chassis, accelerating the development and testing of VNX+ plug-in cards (PICs) compliant with both VITA 90 and SOSA standards.

Introducing the Cheetah Tactical Router as a Typical VNX Solution

Another innovation that can significantly enhance military applications is the Cheetah Tactical Router—a cost-effective, fully managed, military-grade Level 2/3 network switch/router combo with 8 or 16 GbE copper ports. It offers:

  • VNX+ Compliance: Fully compliant with VITA 90 (VNX+), making it ideal for modern defence applications with strict SWaP constraints
  • Ruggedised Design: Built for harsh environments and tested to meet MIL-STD-810G and MIL-STD-461F for vibration, shock, humidity, and EMC
  • Modular and Scalable: Provides 8 or 16 GbE ports, optional LTE/GNSS, PoE support, and a Linux-based OS for custom software integration
  • Applications: Ideal for vehicle-mounted systems, tactical datalinks, and mobile command platforms

Figure 4: Cheetah Tactical Router in rugged VNX+ format (Figure: Sundance)

The Cheetah Tactical Router is designed for tough operational conditions. Its ruggedized design has been tested to withstand severe customer environments, making it ideal for vehicle applications and providing connectivity for situational awareness, internal and external communications, as well as tactical datalink functions. Utilizing a Linux-based operating system, the router can host custom software functions as required by the use case. The system’s modularity addresses a cost-effective approach to provide functionality only as needed. Future-proof interfaces like Gigabit Ethernet, USB3, Dual CAN-FD, and digital I/O make development straightforward.

Conclusion

The VNX/VNX+ standard complements OpenVPX by delivering energy-efficient yet powerful modular technology. Military applications benefit from high computing performance, strong modularity, and long-term viability through standardization. When it comes to small, portable, and integrated devices that must meet SWaP and ruggedness demands, VNX is an ideal solution.

Discover the future of VNX. Get in touch with experts from Sundance/Etion Create today!

 

[Sidebar: Rely on proven technology]
Within VITA, there is currently a working group developing the VITA100 standard, which is scheduled to be ratified in early 2026. There is still a long way to go, but VITA has indicated that it is also planning changes to the form factors. In addition to 3U and 6U backplanes, there will also be 4U backplanes in the future. With this, VITA aims to meet the increased power requirements of current processor technology such as GPGPUs, NPUs, and the latest FPGAs, which are designed to provide higher performance for designs in the VNX, VNX+, or OpenVPX form factors. Cooling and thermal management are also to be improved with VITA100.

However, moving away from the 3U and 6U form factors that have been used successfully for over 40 years presents some disadvantages for developers—think of the Reliant Robin, a car with three wheels—that need to be considered.

  1. Interchangeability: Old VME cards can be easily replaced with new OpenVPX or VNX modules in 3U or 6U form factors. New modules in 4U form factors would no longer be compatible with existing systems, which significantly reduces ease of interchangeability and causes problems when updating to newer systems.
  2. Scalability: Until now, old computer systems could simply be upgraded to newer and more powerful platforms. Introducing a new form factor such as 4U means that this is no longer possible without extensive redesigns.
  3. Size: Compared to 6U, 4U saves space in the control cabinet, but you may have to adapt your entire portfolio to the new form factor, as 4U is not compatible with 3U and 6U. You would have to adapt all reference backplanes and the corresponding development platforms.
  4. Supply chain: It is not yet clear how many manufacturers will produce modules in the 4U form factor. Initially, the number will be manageable. By moving away from 3U and 6U, there is a risk that there will be little choice on the market.

Sundance and Etion Create have been successfully developing and manufacturing 3U and 6U modules in form factors such as VNX, OpenVPX, and VME for many years. Customers can rely on our years of expertise to provide the right product for every application in industries such as military, critical infrastructure, and automation.