The downed Russian drone — the spool of fiber optic cable is visible at right but was not at first ... [+] identified.
When Kalashnikov subsidiary ZALA boasted that their new ‘Product 55’ quadcopter was proof against all forms of radio jamming, this appeared to point to some kind of autonomy similar to what the company had previously displayed. But a captured Russian FPV attack drone uses a very different and quite surprising technology to overcome radio interference: it has no radio but communicates with the operator via a fiber-optic cable spooled out as it flies. Mpo Optic
On March 2nd, Ukrainian military blogger Serhii “Flash” reported a strange new type of Russian FPV kamikaze drone. In addition to the usual warhead, this was carrying a hollow plastic egg containing unidentifiable equipment. Flash asked his readers whether anyone knew what this might be
A few days later, he posted the answer. Ukrainian experts had take the drone apart and established that the mystery device was a spool of fiber optic cable attached to a commercial Chinese-made optical transceiver used for high-speed communications. The markings on the spool showed it held 10,813 metres (6.7 miles) of cable.
This came as a surprise the Flash, but not a complete one.
“At the Hackathon of the Ministry of Defense, there was a participant who proposed to use this technology for UAVs [Uncrewed Air Vehicles] ,” he noted, “but my colleagues on the jury and I doubted that it was realistic. A drone that unwinds a coil of 10 kilometers of cable in the air without breaking the fiber.”
Many online commenters have expressed similar surprise, and many find it impossible to believe that this technique could ever work. But this type of guidance has a long pedigree.
A mobile launcher for the U.S. Army's EFOGM fiber-optic guided missiles
Among the weaponry the U.S. has supplied to Ukraine are thousands of TOW-2 missiles. These are an older type which has been in service with the U.S. since 1970. The name stands for “Tube-launched, Optically tracked, Wire-guided,” the last part because the missile is guided via a pair of copper wires. These are spooled out as the missile flies, and the range of the missile is limited by the length of the wires (2.4 miles).
This approach was adopted because previous anti-tank guided missiles used a radio link which was considered too vulnerable to countermeasures.
The copper wire just carries the control signals for the missile. But with the advent of fiber optics, it was possible to develop an advanced version with enough bandwidth to transmit a video signal back to the operator from the missile. This was the concept behind the U.S. Enhanced Fiber Optic Guided Missile (EFOG-M) program from the 1980s. Being able to see from the missile’s point of view meant the operator could engage targets beyond their line of sight; a light vehicle carrying racks of EFOG-Ms would be able to destroy enemy armor a long range.
Competition from infra-red guided Javelin and laser-guided Hellfire eventually killed off EFOG-M, and numerous other projects made little progress. The technology worked, as test firings showed, but there were other alternatives, and even the long-range Polyphem missile was terminated.
DARPA's Close Combat Lethal Recon drone was a fiber-optic guided loitering munition for urban combat ... [+]
Fiber optic was also a potential technology for drones. In the early 2000’s DARPA developed a kamikaze drone with an explosive warhead under the Close Combat Lethal Recon program:
“… a hand-held, tube-launched, fiber-optic guided, loitering munition suitable for non-line-of-sight (NLOS) target prosecution by individual warfighters in urban environments. … The guided munition will be capable of striking targets from significantly expanded avenues of approach, e.g. over the tops of buildings and around corners, at a distance of up to ten blocks depending on the specific terrain and building features. “
The fiber-optic link was eventually dropped in favor of radio control, but much of the rest of the technology was used in what was to become the SwitchBlade 300 loitering munition made by AeroVironment AVAV and now used in Ukraine.
The technology for controlling drones via fiber-optics already exists, but it is a highly niche area with no broad commercial application. Timbercon, based in Oregon, is a fiber optic specialist with a variety of products for drone control and video transmission; the company web site says “These products are available in a number of standard configurations and can be customized for your specific application.”
The Russian drone uses commercial lightweight fiberoptic cable.
What is interesting with the Russian drone is that this does not look the product of a military lab, but of one of the many small Russian outfits working on drone developments using commercial components. These range from thermal imaging to drones that ‘hibernate’ for weeks waiting to be activated to long-range communication relays. Previously these have been held back by Soviet-style bureaucracy but things may be moving faster now.
The spool of cable and optical transceiver add significant weight to the drone - probably a few pounds - so it carries a much smaller warhead than it could otherwise. But there is a huge advantage. Fiber optical communication cannot be detected and cannot be jammed. This is important in a situation where the cat-and-mouse game of jamming and counter-jamming is a major factor in how effectively drones can fly.
It is also significant to the wider world: the vast majority of counter-drone systems used in the West to protect against terrorist and other malicious use of drones rely on jamming, spoofing or interference with radio signals. If anyone can build a fiber-optic drone in their garage, the threat becomes more challenging.
Optic Cable “I am already asking Ukrainian specialists to test this control technology so that we do not end up behind the enemy,” notes Flash.