Accelerating Delivery of New Electronic Warfare Capabilities with COTS Software Defined Radios

By Jeremy Twaits , Solutions Marketing Manager, NI’s Aerospace

Spectrum superiority has never been more critical to success on the battlefield. Amid an increasingly contested and congested electromagnetic spectrum, the ability to reliably operate communications and navigation systems while deceiving and disrupting the adversary creates a significant tactical advantage. Software defined radio (SDR) provides the ideal platform for developing and deploying electronic warfare systems and the flexibility to adapt to modern and constantly evolving threats.

After a hiatus on travel, the recent Association of Old Crows’ (AOC) annual European summit in Montpellier, France, was the ideal spot for garnering insight into the most pervasive drivers in the development of novel EW (electronic warfare) capabilities. The AOC Europe conference proved a melting pot of old faces and new technologies. Immediately obvious was the value of rapid innovation inspired by COTS tools – from the influence of EW in ongoing conflict, to the rising tide of digital engineering, to the growing need for cognitive techniques.

The Timeliness and Importance of EW

A recurring theme at the AOC Europe conference was the conflict in Ukraine, highlighting the timely requirement for novel capabilities for both disrupting an adversary’s use of the electromagnetic spectrum (EMS) and protecting communications and other assets from being denied spectrum access. It is clear why advanced EM techniques are required as a protective measure against an ensuing threat. It has been widely reported that, in 2022, Ukrainian forces have operated more effectively in the electromagnetic spectrum battlefield than in Russian incursions into Eastern Ukraine in 2014 and 2015. This has been attributed in part to new, more jammingresistant, radios deployed by Ukrainian forces and has contributed to Ukraine avoiding the fog of war that Russia would surely have liked them to flounder within. Additionally, Ukraine has been successful at not only jamming Russian EM devices, but even capturing EW systems – providing vital intelligence on Russia’s capabilities. The game of electromagnetic cat-and-mouse continues relentlessly, and concluding definitive winners and losers in the EMS stands to be difficult or impossible. However, achieving domination of the electromagnetic spectrum is a key contributor to mission success, and forms the backbone to the further trends discussed.

If You’re Going to Fail, Fail Fast

A key part of delivering new EW capabilities stems from flexibility to test new ideas quickly, and to fail fast. Spending time on mocking up boards or designing custom ASICs may be wasted if the concept under research does not yield improvements over existing algorithms, waveforms, or architectures.

A key area of focus on new capabilities revolves around cognitive techniques, and questions on how to prototype and assess them. Cognitive radar and EW systems aim to minimize the load on human decision-making. Let’s take radar for example: Rather than an operator making decisions on operating frequencies, pulse widths, modulation types and so on, a knowledge-aided processer takes input from the receive chain and an environmental database and runs an algorithm to estimate the optimal pulse rate and modulation type for detecting and identifying objects in the radar field of view. The use of cognitive systems intends to drastically reduce the time needed to identify ideal operating parameters.

Whether for cognitive jamming or artificial intelligence / machine learning based receivers, the ability to acquire RF data, process it and make decisions on a processing unit is key. Software defined radios can enable prototyping of cognitive techniques by utilising FPGAs onboard for real-time signal processing, and even offloading tasks to other computing units such as CPUs or GPUs. NI incorporates these processing options into a freely available, open-source reference architecture for rapidly developing a prototyping testbed for EM techniques. This Open Architecture for Radar and EW Research (OARER) is a validated design pattern with assembly instructions,

examples, and a code library. It handles data movement and synchronization across radios, saving researchers and systems engineers from having to build out that infrastructure themselves, removing time-consuming steps and helping them to succeed (or fail, iterate, and improve) faster.

Digital Engineering Moves to the Fore

Linking models from simulation to prototyping to testing (and vice versa) was another key theme explored at the AOC conference. Simulation tools provide a quick and low-cost way of quickly exploring a design space. However, EW transmitters and receivers, and the channel conditions within which they operate, designed in simulation cannot always be fully representative of real-world conditions. Moving signal processing from simulation to a hardware-based prototype has not always been straightforward, so NI and MathWorks have collaborated on improving the transition between tools. This includes the introduction of new software from MathWorks, named Wireless Testbench™. Wireless Testbench provides reference applications for high-speed data transmit, capture, and spectrum monitoring, when paired with COTS USRP software defined radios from NI.

Another aspect of digital engineering coming to the fore is in high-fidelity scene generation for validating new capabilities with flexible RF instrumentation. Taking new techniques straight out to the testing range is an expensive and time-consuming pursuit. It is essential to ensure appropriate test coverage for functionality that could be life-critical, and an open-air range may be an essential step on that path. However, a prudent first step is to assess techniques in a hardware-in-the-loop environment before embarking upon test stages that incur a greater cost. RF phenomenology tools, such as RFView® from Information System Laboratories, can be used for system analysis and algorithm assessment, creating what can be thought of as a digital twin – not for the system under test, but for the environment surrounding that system. This allows researchers or validation engineers to create a virtual world for their system to operate within, with realistic, high-fidelity representation of terrain and clutter.

Figure 1 - NI’s Open Architecture for Radar and EW Research is built on USRP N321 and N320 software defined radio devices and scales up to 32 x 32 channels.

Software Defined Radios in Deployed Applications

The final evident trend was the movement towards deploying open systems in tactical and strategic scenarios. Again, the watchword is pace. One cannot afford to be outpaced by one’s adversary. The pace of equipping the warfighter with effective, novel techniques for electronic warfare is critical. COTS, reconfigurable platforms provide software-upgradable capability, which can be delivered to the field

Another aspect of digital engineering coming to the fore is in high-fidelity scene generation for validating new capabilities with flexible RF instrumentation.

Figure 2 - SkySafe’s rugged drone defense system contains a USRP X310 SDR from Ettus Research, an NI brand.

much faster than hardware revisions. And utilising COTS hardware that spans the lab and field removes much of the code refactoring that is required to move algorithms into mission hardware.

Software defined radio devices have made their way into deployed systems in a variety of form factors. From pole-mounted, IP67-rated monitoring systems, to dronecarried, low-SWaP (size, weight, and power) radios, manpack deployments, fixed signals intelligence sensor sites, and perhaps most prominently, counter-drone systems. For example, SkySafe, a global leader in drone airspace management, elected to deploy their drone defense system upon NI COTS SDR technology. Combining these SDRs with open-source software, SkySafe can rapidly adapt to evolving threats by deploying new algorithms. Compared to implementing changes to mission hardware, this greatly reduces the time and cost to realise new capabilities. SkySafe’s CTO, Scott Torborg, stated that, “The NI Ettus Research USRP X310 is the only commercially available SDR with the openness and raw RF and DSP capabilities to meet the needs of this rapidly evolving drone threat.”

Deployments on open architectures are increasingly popular for taking advantage of interoperability between modules and for the relative ease of technology refreshes as components are swapped in and out. Accordingly, Curtiss-Wright have built a rugged, user-programmable SDR, with a design based on the Ettus Research E320. The module is aligned to The Open Group Sensor Open Systems Architecture™ (SOSA) and the US Army’s C5ISR Modular Open Suite of Standards (CMOSS) Technical Standards. Importantly, the module is compatible with the USRP Hardware Driver (UHD), allowing IP to be transported from the lab to rugged deployments without rewriting software.

Where Next?

Given our decades of experience in the Defense Market, we have compiled prominent concerns and misconceptions that technology companies have about entering this challenging arena.

The nature of EW dictates that there is mystery over precisely what threats will be encountered. Broadly, forces will need to continually enhance electronic protective and support measures, while improving their own ability to conduct targeted electronic attacks. This will drive radios to scale to wider bandwidths, higher frequencies, and larger channel counts, incorporating more powerful, heterogeneous processing options and streaming more data than ever before. COTS software defined radios offer the ideal flexibility for coping with uncertain threats, and for developing and deploying the capability that is needed both now and into the future.