What We've Learned About SDRs From Russia's War On Ukraine

By John Oncea, Editor

The War in Ukraine has shined a spotlight on Software Defined Radio as both Ukraine and Russia have leaned into the technology. What has been learned about the performance of SDR and how is that knowledge being leveraged?

The thoughtful, strategic use of the electromagnetic spectrum to prevent others from doing the same, commonly referred to as electronic warfare (EW), is an ecosystem of many components including these three: electronic attack, electronic protection, and electronic warfare support measures. Defined, these three components are:

• Electronic attack: The use of electromagnetic or directed energy (DE) against personnel or equipment to degrade or destroy combat capabilities.
• Electronic protection: Efforts or equipment directed toward the protection of persons or materials from the effects of EW. These include the unintended side effects of friendly EW, as well as enemy actions undertaken to degrade or destroy one's combat capabilities.
• Electronic warfare support: Actions and resources committed toward locating, identifying, and if necessary, intercepting, or neutralizing sources of electromagnetic energy that pose an immediate threat.

The applications of EW are diverse, ranging from navigation and target location with radar to disrupting an enemy's mechanical and electromagnetic systems with electronic bombs. EW can be employed to deceive or confuse the enemy, such as in radar jamming or the transmission of misleading signals. Additionally, it can be utilized as a DW to disable infrastructure.

Software Defined Radio (SDR), a software-based radio communication system, is also part of the EW ecosystem and it plays a crucial role in the military’s secure communications. SDRs enable the implementation of EW’s three components defined above and are made up of the radio front end (RFE) and the digital backend. The RFE can consist of multiple independent receive and transmit radio chains, each responsible for receiving and/or transmitting signals that can be tuned to a center frequency across a wide range.

SDRs are “built with open architectures that allow for rapid adaptation to enemy capabilities and efficient introduction of emerging technologies,” writes Avionics International, and they will help the U.S. Army “field a mobile battlefield network simultaneously modular, open, and secure from interference from enemy EW systems.”

SDRs, Ukraine, And Russia

“Although military technology has come a long way over the decades, the evidence suggests radio still plays an important role,” writes Radio Fidelity. Here, we take a look at how radios are influencing the progression of Ukraine and Russian war starting with Russia’s ability to ground unmanned aerial systems in Ukraine by jamming and spoofing signals required for the SDRs in these tools. This action rendered the Ukrainians incapable of delivering surveillance and intelligence from the air and, concurrently, the Russians attempted to jam air defense radars, nullifying command, and control efforts.

“At the same time, Ukrainian troops have leveraged their electronic warfare strategies,” Radio Fidelity reports. “For example, the country’s forces have utilized jamming systems supplied by the U.S. to prevent Russian tactical communications. Since the Russians haven’t been able to leverage single-channel ground and airborne systems for radio communication, they’ve often relied on unencrypted radio systems and cell phones, making them more susceptible to Ukrainian exploitation.”

The Ukrainian military has successfully taken advantage of vulnerabilities in the Russian electronic warfare systems, including intercepting transmissions from well-known tools like the Krasukha-4 and Leer-3, despite their greater size and power.

Perhaps the biggest surprise, however, has been how poorly the Russians have performed using technology such as radios. “Though Russia has overhauled and improved its military technology in recent decades, focusing on modernizing its communication hardware, they’ve struggled to implement new solutions into its efforts within Ukraine,” Radio Fidelity writes. “Specifically, many Russian military transmissions have occurred almost exclusively over unsecured lines.”

This has allowed the Ukrainian military to intercept Russian communications, often aided by SDR radio kits supplied to them by the New York-based nonprofit group American Ukrainian Aid Foundation. According to Forbes, the SDRs are allowing Ukraine to “locate Russian radio emitters, from command centers to drone operators.”

“In a traditional radio set, the signal from an antenna is processed by dedicated hardware – amplifiers, filters, modulator/demodulators, and other components. This means that each radio set is dedicated to one particular type of radio signal, whether it is a 5G cellphone, AM radio, digital television, or WiFi.”

With SDR, the antenna is the only hardware needed. All signal processing is done digitally using a computer. By adjusting the programming, an SDR can capture signals for various waveforms such as cellphones, radio, Bluetooth, and more.”

Applying Lesson Learned Domestically

Major General Jeth B. Rey, director of the Network Cross-Functional Team within Army Futures Command, said the war in Ukraine validates the U.S. Army’s pursuit of secure communications capabilities, Avionics International reports. “What we are seeing in Ukraine reinforces the need for secure communications and greater mobility and survivability,” Rey said. “There is also great innovation occurring with our soldiers who are supporting operations in Europe.”

SDRs that feature reconfigurable, open-architecture hardware and software capable of digitally processing data will be key to the Army successfully achieving its goal as SDRs can tune to any frequency band and use multiple waveforms through plug and play software applications built to published Army standards.

Radiofrequency devices are important in military technology for communication, recognition, navigation, and spatial awareness. SDRs are the primary RF transceiver in modern military applications, including radars, SATCOM, tactical radios, and EW/SIGINT devices. As such, the continued development and reliance on SDRs will only grow in importance and suppliers of this technology will need to work quickly to keep up with the needs of the military.