Russia has tested a new radar system that can evade detection by enemy drones or aircraft, its developer told the state-run RIA Novosti news agency on Friday.

Passive radars operate without a transmitter, instead receiving signals from other objects to track targets. Russia’s new passive radar, called Tropa (Russian for “path”), uses communication towers to locate signals without transmitting one itself, RIA Novosti reported. 

“That means you can’t see or hear it,” Alexander Petrov, the head of the OKB-Planeta manufacturer, was quoted as saying at Russia’s annual military showcase near Moscow.

Tropa successfully intercepted an aircraft signal from communication towers within city limits during tests in the city of Tver northwest of Moscow.

The invisible radar has military as well as civilian applications, Petrov said. Private buyers, he added, could use the equipment to “keep drones from spying on them.”

OKB-Planeta is owned by Russia’s private defense solutions holding company RTI. 

The military show featured another passive radar, Avtobaza-M, developed by the Moscow-based Electronic Warfare Science and Technical Center defense manufacturer.