Ukraine Uses Off-The-Shelf Electronics To Target Russian Communications

A US-based non-profit organization supplies Ukrainian forces with advanced electronic warfare equipment assembled from simple off-the-shelf components. The secret is a new technology known as Software defined radio (SDR), which can locate Russian radio transmitters, from command centers to drone operators. Previously, this kind of capability required expensive, high-end military equipment.

Serge Sklyarenko says that his organization, American Ukrainian Relief Foundationbased in New York, supplies Ukrainian intelligence with a number of universal SDR radio sets.

“The beauty of them is that they are software-defined, which means they can be reprogrammed in the field to suit multiple use cases,” Sklyarenko told me.

In a traditional radio station, the signal from the antenna is processed by special hardware – amplifiers, filters, modulator/demodulators and other components. This means that each radio receiver is designed for a specific type of radio signal, whether it is a 5G mobile phone, AM radio, digital TV or WiFi. In software-defined radio, the only dedicated hardware is the antenna. All signal processing is done digitally with a computer. Simply by changing the programming, the SDR can retrieve the signal for a cell phone, radio, Bluetooth, or any other defined waveform. One device can do it all.

Although simple in theory, SDR initially required an enormous amount of computing power and took pressure from DARPA in 2010 to make the technology viable. DARPA kept pouring research funds for the development of SPT including an advanced system on a chip demonstrated by Raytheon last year using standard Intel

Open source SDR kits are now available on the consumer market and Ukraine is making good use of them.

“SDRs are a basic five-channel receiver with coherent control,” says Sklyarenko. “While signal analysis is generally quite secret, we sent these radios with the primary purpose of ‘fox hunting’ or direction finding. Essentially, they are listening for fake radio broadcasts.

A fox hunting is a competition between radio amateurs to find a hidden radio transmitter, usually just for fun. But in this case, the game is deadly serious.

Analog direction finding is essentially a matter of rotating a directional antenna to find the strongest signal; by using several antennas or moving to different locations, the source can be located by triangulation. Digital bearing is more complex and uses the phase difference between the signal in multiple channels.

Before this type of radio direction finding equipment was bulky and could cost tens of thousands of dollars. The new technology shrinks it down to the size of a palmtop and with Open source SDR software and cheap processors like Raspberry Pi cuts costs down to a few hundred.

Since the beginning of the war, Ukrainian volunteers have been able to listen to much of the Russian military radio traffic, due to the Russian lack of modern radio equipmentand even silencing them by broadcasting noisy heavy metal on the same frequency. Foxhunting SDR sets will allow Ukrainian operators to detect Russian transmissions and target them with mortars, artillery, HIMARS or other weapons.

In particular, the technology can locate Chinese-made DJI quadcopters used by Russian forces as well as their operators on the ground.

“It’s common knowledge that you can use SDR to find DJI,” Sklyarenko says.

SDR receivers can locate all radio transmitters over a wide area, including, for example, air defense radars and Russian electronic warfare systems used to jam GPS. Russia has a a wide variety of such systems. For more distant sources, this will require a network of SDRs linked together to form a large-scale sensor network. This concept has already been explored at DARPA Radio map project. Ukraine may be the first nation to implement this concept on a large scale, thanks to an abundance of low-cost receivers.

“It would be great to cover the whole country with SRT,” says Sklyarenko.

The receivers are so small that they can even be carried on drones. Signals reconnaissance is useful not only for locating individual transmitters, but can identify the position of units from their radio traffic and spot movement when HQ deploys to an area.

While radio intercepts can determine location, the most important Russian military communications are encrypted, making them impossible to penetrate. That may change.

“We hypothesize that SDRs can be used for much more interesting applications, such as intercepting transmissions for supercomputers to decipher. But they won’t tell us”, says Sklyarenko. “All we know is that they’re in high demand and we’re happy to help ship them.”

More details about the work of the American Ukrainian Aid Foundation (501c3 public charity) and how to support it can be found on the website here.

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