By: Mark Littlefield, Director of System Products, Elma

At the GVSETS conference in Detroit in August 2024, I presented a white paper titled "VNX+ for Ground Vehicle Applications” that examined how VNX+ (VITA 90) and its related content captured in the latest version of the SOSA® Technical Standard can be applied to ground vehicles. This blog is a summation of that paper.

Applying VNX+ to Autonomous Ground Vehicles

Vehicle electronics have always been constrained by space, weight, and power (SWaP). Given the huge increases in bandwidth and processing demand seen in recent years across autonomous vehicles, this is especially true for high-performance sensors and communications electronics.

Additionally, the systems needed for unmanned vehicles often require more onboard functionality, such as vehicle navigation and control electronics, as well as the sensor payload and yet are significantly smaller than those found in manned vehicles.

VITA 90, also known as VNX+, offers an alternative form factor to 3U OpenVPX for these SWaP-constrained applications, offering the same technical features, but in a form factor about 30% of the size. Adding to its utility, VNX+ is now a fully supported form factor in the latest snapshot of the Sensor Open Systems Architecture (SOSA) Technical Standard.

VNX+’s Useability Across Different Platforms

With an eye on supporting high-performance, but SWaP-constrained, sensor platforms, VITA, with input from SOSA, crafted several VNX+ slot profiles to become the building blocks for these systems (Figure 1). They include:

• 400-pin general purpose payload (VNX.PL-1-HH.400-7.2.1.1-<General SBC>)
• 320-pin general purpose payload with a half-aperture for blind-mate coax and/or optical connectors (VNX.PL-1-HH.320-7.2.2.1-<General SBC>)
• 400-pin switch (VNX.SW-1-HH.400-7.4.1.1-<7DP/8CP Switch>)
• 320-pin switch with a half aperture (VNX.SW-1-HH.320-7.4.2.1-<5DP/5CP Switch>)
• 320-pin radial clock based on a payload template-suitable for a processor that can provide radial clock (VNX.SW-1-HH.320-7.5.2.2-<7REFCLK/7AUXCLK Overlay>)
• 320-pin radial clock supporting a large number of slots (VNX.RC-1-HH.320-7.5.2.1-<22REFCLK/22AUXCLK>)

 

Figure 1. Most slot profiles are based on a profile template defined by VITA 90.0 to maximize design reuse in both PIC and backplane designs. Pictured are the 400-pin payload (L) and the 320-pin network switch (R) profiles.

Aside from the high-density radial clock, all slot profiles support the same utility functions and most of the communications protocols found in OpenVPX (some of the older protocols have been dropped due to obsolescence).

To further increase design reuse, VNX+ incorporates common I/O ports in predictable locations in the payload profiles. Typical power management for a VNX+ system is in the 35W range for conduction cooling, with opportunities for higher densities using more innovative chassis designs and cooling approaches.

The control plane and data plane have individual command/data inter-PIC paths that are identical to OpenVPX, making them easily integrated into open standards-based DOD architectures, like VICTORY. The control plane is based on Ethernet.

These attributes mean that system designers and integrators can build high-performance sensor systems much like with OpenVPX, but within the SWaP constraints needed for smaller systems, a task impossible to do with OpenVPX. This is particularly attractive to autonomous platforms in ground vehicles.

The following seven documents contribute to the definition of VITA 90’s form factor and infrastructure:

•  VITA 90.0: VNX+ Base Standard
•  VITA 90.1: VNX+ Profile Tables
•  VITA 90.2: VNX+ Optical and Coax Apertures
• VITA 90.3: VNX+ Power Supply and Storage Modules
• VITA 90.4: VNX+ Cooling and Mounting Systems
• VITA 90.5: Space VNX+
• VITA 90.7: VNX+ Optical and NanoRF Coax Apertures Standard

Advancing Application Capabilities Through VNX+

VITA 90 VNX+ is expected to be applied to ground vehicle applications in the coming years – most especially in autonomous ground vehicles, where systems will be much more compact and space-constrained. Applications such as 360° situational awareness systems, active protection systems, SIGINT/EW, software defined radios, and network processors are all good candidates for VNX+ implementations.

As we move into 2025, new VNX+ products will be hitting the streets, giving integrators more options to create smaller, open standards-based systems using interoperable components, saving cost, time and engineering resources.