The commercial drones which make up the bulk of Ukraine’s force operate on known radio frequencies, making them highly vulnerable to jamming. A report by UK thinktank RUSI suggested that Russian electronic warfare took out 90% of Ukraine’s drones in the early stages of the war. Now, however, things seem to have changed, and Russia’s ability to jam drones has been neutralized by smart, but currently mysterious, technology — but this may be a temporary victory.
Jamming Steps Up
Jamming was always going to be a problem using cheap quadcopters in war. Consumer drone controllers operate on known, legally-controlled frequency bands. All a jammer needs to do is to transmit enough radio noise on the same frequency as the drone controller, and the drone’s control signal disappears in a blizzard of static and it stops responding. And as the war progressed, Russia brought up increasingly powerful and sophisticated jammers to target the drones which were directing artillery fire on to their positions and dropping grenades into their trenches.
One drone operator told the Guardian that late last year drones could fly 6 km (3.7 miles) beyond the frontline, but in Bakhmut more recently they flew “1 km maximum, sometimes it was not possible to cross the border.”
I have heard the same story from other drone operators, and this steady shrinking of operations was echoed in the media with one Ukrainian Colonel complaining in a newspaper interview in March that quadcopters used by the infantry lasted “half a day,” compared to those used by the artillery which can hang further back from the front line and have a lifetime of a month.
A RUSI report in May suggested that Ukraine was losing 10,000 drones a month, mainly to jamming. Ukraine appears able to sustain this level of drone losses, but perhaps more serious is the effect on operations. When the drones cannot fly, directing artillery becomes vastly more difficult.
Reports from both sides show they are pushing more jammers into the field to counter the drone threat, and these seem to have had an effect. Russian jamming even seems to have affected U.S.-supplied JDAM bombs and Excalibur guided artillery rounds.
However, in the last few weeks things seem to have been changing. We have seen a marked uptick of new drone videos during the counteroffensive, showing small drones directing artillery fire and bombing Russian trenches and vehicles, while small FPV kamikazes appear to be taking out significant numbers of Russian tanks. This is surprising because the counter-offensive means Ukrainian drones have to push ever further into Russian-controlled to carry out their missions.
Rather than being completely eclipsed, Ukrainian drones seem to be having a resurgence. How is this possible?
Inside Information
The answer is at least hinted in a subtitled video posted by Mykola Volokhov, known by the call sign Abdula, commander of the Terra drone unit, which has posted many videos of combat operations. In the video Volokhov mainly talks about the different types of drone bombs that his unit has used – one derived from a U.S.-supplied 40mm grenade comes out as favorite – and the 3D-printed drop mechanisms and means of attachment to drones. He also mentions his units experiments with using FPV drones as dive bombers, a technique which has only recently emerged.
Then, nineteen minutes in, he mentions electronic warfare.
“We encountered communication problems. For a long period of time the opponent dominated us,” Volokhov says, and describes the familiar pattern of growing interference. In Kherson Terra’s
LUNA
But, as Volokhov notes, things have now changed.
“But this problem was overcome and now it is not with us. No problems! I could show you, but I probably won’t, because there is a certain known-how of ours. I would not like to reveal it.”
He looks offscreen, as though there is a piece of equipment he is considering showing us, but decides against it.
“Maybe I’ll tell you all about it later,” Volokhov says, then goes back to summarizing drone bombs.
Previously, Ukrainian drone operators worked out how to modify the firmware on their drones to counter DJI’s AeroScope tool which locates quadcopters and their operators. To make things easy for drone operators, Ukrainian engineers built a black box called Olga which plugs into the drone’s USB port and makes the necessary changes automatically. This update means that instead of transmitting their actual locations, the drones claim to ne at zero latitude, zero longitude, a spot known as Null Island.
Jamming is harder to counter, but there are plenty of known techniques from the military world such as the use several antennas to create a highly directional receiver which can screen out jamming. A notch filter blocks out signals which are not precisely those of the controller, reducing the noise produced by jamming. And smart receivers can switch frequency to find one which is not jammed. But we do not know which of these approaches Ukraine uses – if any.
In Electronic Warfare Nothing Is Permanent
“It’s certainly plausible that they have found a way to counter Russian jamming for a time,” says Dr Thomas Withington, a military analyst specializing in electronic warfare But he emphasizes that anything the Ukrainians do will not be a permanent solution. Electronic warfare is a continuous arms race, as each countermeasure is met with a new counter-countermeasures in a never ending game of cat and mouse.
“And during a conflict, the innovation accelerates,” says Withington.
An alternative method is to target the jammer and physically destroy it. Blasting out a lot of noise requires a powerful transmitter which can easily be located. This makes it easy to hit with artillery or mortar fire. It might even be targeted by a drone which homes in on the jamming signal itself, like a low-cost version of a HARM missile.
Other sources mention rumors of Ukrainian projects to counter jamming, but everyone I contacted preferred not to give away anything at this stage. There will be plenty of stories told after the war, but for the time being, however Ukraine beating drone jamming is very much a secret weapon.
Volokhov and others on the Ukrainian side believe they can continue using commercial drones to wreak havoc on Russian forces. There are likely to be more twists and turns in the drone arms race, the pendulum may swing back towards the jammers again and the drones may again be pushed back. For now, the quadcopters are winning.
Read the full article here