The advent of drone warfare as a major part of the Ukraine war with Russia has turned modern conflict, and the weapons we have traditionally used for it, totally on its head: Swarms of drones, which cost next to nothing relatively, can now threaten U.S. aircraft carriers; potentially, swarms of miniature drones the size of insects, could decimate urban areas, and even armies. It’s a bit like the advent of tanks in World War I, which totally changed the battlefield format that had been the standard for centuries. However, thankfully, each new major advance in warfare is usually, eventually, balanced by new technology. Today that process appears to be considerably speeded up.
I read recently that a British company has developed a simple, relatively cheap, laser weapon that can target drones and destroy them, obviating the necessity of using extremely expensive missiles. Last month, the Economist reported that a group of engineering students at the University of Toronto had developed a system to use acoustic waves to disrupt the electromechanical sensors that drones need to fly; in other words, shoot powerful sound waves at them.
The four students who developed this system initially repurposed small car speakers to cobble together a contraption for “blasting a drone with sound”. It worked in early tests, although only at close range; drones 50cms away wobbled, and at 25cms they crashed. In the spring of 2024, the students beefed up the contraption’s power to produce ultrasonic waves. They then entered Canada’s Defence Department’s competition for counter-drones. They tied for second place, winning C$375,000 (US$262,000).
The students formed a small startup company, called Prandtl Dynamics, and are now developing a battlefield, suitcase-sized, model that will disable a drone at a range of 100 meters.
Prandtl’s system concentrates energy into a narrow acoustic “laser” that disrupts the drone’s gyroscopes; all drones use gyroscopes to maintain stable flight. The system can not only send a disrupting sound wave at the drone, it can detect incoming drones, and aim the acoustic beam.
The system records sound waves from approaching drones and uses a computer costing C$30 (yes, C$30) to crunch data from a sky-scanning camera to locate the drone, determine its trajectory, and aim the destructive acoustic “ray”. Prandtl hopes to stretch the range of this system to 150 meters, based on the fact that the current effective range of battlefield tactical jammers in the Russian/Ukrainian war only have an effective range of just 50 meters.
In addition, many of the newer battlefield drones are impervious to current jammers and many have a built-in mapping system that avoids the requirement of ground control. Prandtl’s acoustic system would be effective against all of these because it disrupts the drone’s stabilizing gyroscopes, not its control system.
The Prandtl system can also gain control over the drone gimbal or camera shutter systems. “We can blind the drone, or we can crash the drone”, said the company’s boss. Either way, it seems as though innovative technology at the most basic level may well be able to counteract one of the most-scary advances in warfare, and at a very cheap cost.
The company is currently developing a 4kg backpack model to protect foot soldiers. It believes that unit can be manufactured for less than US$1,400, which is ridiculously cheap for military equipment. The company is currently fielding inquiries from America’s armed forces, Ukrainian defence contractors and many others.
There is also the possibility of civilian use. Current regulations make conventional jamming of pesky civilian drones illegal, but disabling their cameras might be a more acceptable public safety approach than bringing them crashing down on unpredictable trajectories.
