Fiber Optic Bird’s Nest Heralds A Fiber Drone Summer In Ukraine

A bird’s nest incorporating fiber optic cable is a striking sign of how much debris from fiber-guided FPVs now litters the landscape of Ukraine. Other images show fields glittering with fibers like spiderwebs where dozens of drones have passed overhead. Meanwhile social media fills with hide-and-seek videos as Ukrainian drone pilots use their new ability to go inside buildings to hunt Russian vehicles.The non-toxic fibers may not harm birds, but they signal extreme danger to humans. Fiber drone summer is starting.

Fiber Evolution

Most FPV attack drones rely on a radio link to the operator, which can be an Achilles’ heel. Fly too low, or behind a hill and the connection may be lost. More commonly though, FPVs are lost to jamming, up to 75% of them. Anecdotally as many of the losses are ‘friendly fire’ rather than enemy electronic warfare. Jammers give imperfect protection against FPVs, but many rely on them.

Fiber drones, an idea DARPA developed for its Close Combat Lethal Recon drone in the early 2000’s but never fielded, solve the radio reception problem. The drone pays out a fiber-optic communication cable as it flies and is immune to jamming. And while other FPVs may be detected by their radio emissions, fiber drones give no such warning.

The Russians were the first to field fiber drones, barely more than a year ago, first in small numbers and then at scale. Ukraine has been working hard to catch up. According to Ukraine’s Minister of Digital Transformation (and de facto drone supremo) Mykhailo Fedorov, 15 companies now make fiber drones. Much of this rapid progress has been fostered by volunteers like former U.S. Marine Troy Smothers, an American who took his fiber drone design to Ukraine to demonstrate the technology and help build a local industry.

Now we are seeing the results, and in particular fiber drones going where radio FPV cannot. Because any vehicle in the open gets spotted and destroyed by drones, the Russians hide their tanks and other armor in hangars, farm building and garages. These are now vulnerable, as Ukrainian fiber FPVs infiltrate through windows, doorways and other openings to destroy hiding vehicles. Just parking a T-72 out of sight underneath a structure is no longer any protection against being found and destroyed.

Extending Range

The very first fiber drones only had a range of a few kilometers, but this has steadily increased. Drones with 10-15 km of cable are now common. Much greater ranges are possible. Ukrainian troops recently claimed to have hit targets with a fiber drone from 42 kilometers away. A Russian video shows a claimed 50-kilometer spool of fiber weighing less than 4 kilos – too big for many FPVs, but suitable for larger models with a reduced bombload. Ranges are likely to increase and weights decrease with better fiber.

Fiber FPVs are increasingly used for ambush attacks in which the drone lands and waits for a target. Previously in such attacks the ambusher lay dormant to save batteries, waiting for a signal from a scout drone that a target was approaching. But because fiber drones require less power to maintain communication over long range, they can lurk by a track or road for an extended period.

The Russians have recently shown off a more advanced version of this concept, a small tracked robot with a fiber connection acting as carrier for a fiber FPV. There are no signs that this has been used in action yet, but it could significantly extend both the reach and ‘loiter time’ for FPV attacks. Uncrewed vehicles with more FPVs could stage miniature Operation Spiderweb attacks of their own.

Countering Fiber Drones

At present there are no good countermeasures against fiber drones.

Netting may catch a drone before it reaches its target, but the smallest gap can be fatal as this video of a drone slipping through Russian anti-FPV netting shows.. The videos above show that no building is secure against fiber drones unless all the possible entry points are covered.

People often suggest tracking the fiber cable back to the operator, but as the images of fields covered in cables show, this is now virtually impossible.

Cutting the cable is another common suggestion, and one video is claimed to show a quadcopter cutting an FPV control fiber with its rotor blades (see below). However, it is not clear that this is what the video actually shows, and in any case, this seems to have been a one-off. Detecting a fiber drone as it comes in at high speed, getting behind it, locating the cable and cutting it are all challenging.

Shotgun-armed drones are useful for shooting down other quadcopters, but chasing FPVs is another matter. Birds of Magyar have intercepted some Russian fiber FPVs with the aid of tactical radar, but the coverage seems to be limited.

Quite likely we will start to see dogfights between fiber FPVs and interceptors. These engagements will need to be automated because of the speeds involved.

The numbers of fiber drones on both sides are increasing fast, and work on counters continues. Nobody yet knows how long the fiber drone summer will last, or what could bring it to an end.