Ukraine’s cheap sensors are helping troops fight off waves of Russian drones

RAF FAIRFORD, England—Ukraine has a network of almost 10,000 acoustic sensors scattered around the country that locate Russian drones and send targeting information to soldiers in the field who gun them down. 

Dubbed “Sky Fortress,” the concept was developed by two Ukrainian engineers in a garage who put a microphone and a cell phone on a six-foot pole to listen for one-way UAVs, said Gen. James Hecker, commander of U.S. Air Forces in Europe and Africa. 

“They put about 9,500 of these within their nation and now they get very accurate information that is synthesized in a central computer and sent out to mobile fire teams. And on an iPad, they get a route of flight of these one-way UAVs coming in, and they have a triple-A [anti-aircraft] gun and a person with six hours of training can shoot these down,” Hecker told reporters at the Royal International Air Tattoo on Saturday. 

About three months ago, Russia sent a salvo of 84 UAVs into Ukraine, and the system helped the defending troops shoot down all but four, Hecker said. 

The system was so effective that the engineers behind the system were invited to demo it at Ramstein Air Base in Germany, Hecker said. Other countries are looking at acoustic sensors, he added, noting that Romania recently did a demo with the system.

Each sensor costs about $400 to $500, he said, which suggests that the entire network costs less than a pair of Patriot air-defense missiles. 

Hecker said the U.S. and allied militaries should look for their own ways to dramatically lower operational costs. In April, the U.S. expended missiles worth millions of dollars to take out $30,000 drones launched at Israel from Iran and Iranian proxies.

“That's why I challenge industry, I challenge the NATO air chiefs to come up with cheaper, more creative solutions that will put us maybe, hopefully on the right side of the cost curve, but if not, an equivalent cost curve. Likewise, we need to develop equipment at NATO to put Russia on the wrong side of the cost curve, should we have an Article Five situation,” he said.

Patriot and other heavy-duty air defenses remain vital for Ukraine, whose forces and civil infrastructure have been increasingly hammered by Russian ballistic missiles. 

“What we're seeing from the Russians is increased use of ballistic missiles, and that's primarily because of North Korea providing ballistic missiles to them, and that obviously concerns us, but we are making sure that we equip Ukraine so that they can deal with that threat,” Hecker said.  

Hecker was asked about Ukraine’s prospects for survival. 

“A couple months ago, I was a little bit nervous because the Ukrainians were starting to run short on some of the munitions that are required for defense as well as offense. But through the Ukrainian Defense Contact Group, Secretary Austin and the other defense ministers have stepped up to the plate and recently given Ukraine a lot of equipment that they really needed. So that gives me a little bit more hope as we go on,” he said.