US Military ‘Mighty Impressed’ By Ukraine’s Acoustic Sensor Network That Helps To Detect, Identify & Hunt Russian UAVs

The conflict in Ukraine has sparked a wave of innovation, using affordable solutions to counter modern threats. A recent development is the advanced network of acoustic sensors deployed in Ukraine, which has proven so effective that it has prompted the United States to contemplate implementing a similar system. 

Speaking during a discussion at the Hudson Institute on July 24, the commanding general of the US Army Space and Missile Defense Command, Lt. Gen. Stephen Gainey, said the US should include a low-cost acoustic network developed by Ukraine in its air defense systems to identify aerial threats.

This technology, made up of thousands of sound sensors throughout Ukraine, helps to detect and identify incoming Russian kamikaze drones, alert conventional air defenses in advance, and mobilize improvised drone-hunting teams to neutralize them. Ukraine thus possesses a “low-cost defeat” system.

The Commanding General said with conviction that the United States should find a way to incorporate that type of low-cost capability into its system. He emphasized that the US military could incorporate and combine some of that less expensive capability with some of the country’s existing capabilities.

“Their use of acoustic sensors has proliferated across the country to the point now where they’re almost positively identifying drones in the distance because of this acoustic and the fireteams attached to that acoustic, low-cost capability that they’ve developed and proliferated,” Lt. Gen. Stephen Gainey stated.

“The ability to be able to disperse our capability [across a full 360 degrees] and be able to respond to several different threats simultaneously” is one of the most important lessons that the United States might learn from Ukraine, according to Gainey. However, he did not elaborate on the specifics of how this integration may materialize.

The remarks come at a time when drone warfare is dominating modern combat, as seen in multiple battlefields and flashpoints around the world. The Pentagon has noted that the US is also invested in developing a counter-unmanned Aerial System (C-UAS) and the focus is on developing cheaper solutions.

Earlier this year, for instance, the Undersecretary for Acquisition and Sustainment, Dr. William A. LaPlante, stated at a Center for Strategic and International Studies event that, given the increasing role of drones in state-on-state conflict, counter-UAS requires urgent focus. An array of systems, ranging from directed energy weapons (DEWs) to Electronic Warfare (EW), are being worked out for deployment.

The success of acoustic sensors in tackling the drone threat from Russia has particularly been of interest to Washington.

Ukraine’s Potent Acoustic Sensors Network 

Acoustic detection systems feature microphones and software to analyze the environment and detect approaching UAVs. Ukraine’s acoustic air target detection system effectively locates Russian attack drones and works together with its air defense systems.

Kamikaze drones pose a massive threat as their infrared and radar signatures are minimal, precluding engagement with MANPADS (Man-Portable Air-Defence Systems). The drone’s cross-sectional area during its terminal dive reduces to an extent that engagement with air defense guns becomes difficult.

Nonetheless, these drones produce a significant amount of noise that Ukraine’s acoustic sensors pick up on. Despite their small size, the piston engines of kamikaze drones like the Shahed-136 create an intense sound that can often be startling.

Constructed robustly with thousands of sound sensors across the country, the airspace monitoring network has proven to be an invaluable resource for tracking and identifying Russian drones operating during the night.

In March 2024, General James Hecker, Commander of the US Air Forces in Europe and US Air Forces Africa and the Commander of the Allied Air Command, said the idea, known as “Sky Fortress”, was created in a garage by two Ukrainian engineers who mounted a cell phone and a microphone on a six-foot pole to detect one-way UAVs.

Hecker said, “Ukraine had to improvise to track numerous objects. They took 8,000 acoustic sensors and installed them on 6-foot poles all over the country. The microphones were placed so that they could determine the direction of the drones.”

At the time, Hecker noted that the Ukrainian defense forces were able to shoot down all but four of the 84 UAVs that Russia once dispatched into Ukraine. According to him, the cost of each sensor is approximately $400 to $500, meaning that the total cost of the network is less than that of two Patriot air defense missiles.

Mauro Gilli, a senior researcher in military technology and international security at the Swiss Federal Institute of Technology in Zurich (ETH-Zurich), explained, “The system of acoustic sensors strategically placed to enhance capacity to detect incoming attacks by capturing sound emissions of missiles [or aircraft] that try to avoid radar detection (such as flying very low, for example over rivers).”

The acoustic sensor network’s early warning system allows Ukrainian forces to neutralize recognized targets by quickly responding to threats with low-cost weapons like anti-aircraft guns. This proactive strategy has been crucial in strengthening Ukraine’s military position against changing security threats, especially in light of the asymmetric threats.

The early detection of drones also means Ukrainian forces don’t have to train expensive missile defense systems to take down these cheap drones. Ukraine has used several improvised systems to detect drones. For instance, several volunteers in Ukraine use small hand-held drone-detecting devices such as sensors or searchlights produced by start-ups. The acoustic sensor is a more potent system.

It is unclear how the information from the sound sensors is shared, but it could include using the volunteer-run, an ad hoc drone spotting network that Ukraine has had in place for a while, which lets users broadcast alerts using the online messaging app Telegram. Ukraine has made extensive use of messaging apps to relay information about incoming aerial targets spotted by volunteers since 2022.

If the US or NATO were to adopt these sensors, the information that such a system offers might be combined and fused with conventional air defense sensor data, greatly enhancing the overall quality of an integrated air defense system (IADS).

Hecker revealed that NATO was exploring immediate, cost-effective measures to counter one-way attack drones even as nations consider longer-term investments in airborne early warning (AEW) platforms. One such strategy involves evaluating and deploying an extensive network of acoustic sensors developed by Ukraine.

The US has invested in protecting its military installations from hostile UAVs. Thus, an acoustic sensor network would be equally useful in homeland defense.