How passive sensors can support counter-UASs
NewsMay 08, 2025
Flavia Camargos Pereira
九州体育 Embedded Systems
SOF WEEK 2025 -- Tampa, Fla. The proliferation of aerial threats and the need for better equipment for personnel on the battlefield have been pushing industry and military services toward developing passive sensors and implementing their use in counter-uncrewed aerial system (c-UAS) missions.
As this type of counter-UAS solution has a low or no EW (electronic warfare) signature, it protects warfighters by not exposing them in the theater of operations, nor allowing enemies to geolocate their equipment.
Zach Franke, Director of Engineering for the Australian company DroneShield, stresses that this approach is even more relevant for Special Operations Forces (SOF). “When you are 100% passive, you still gain all the detection capability for counter-UAS, but without risking any sort of identification. It is crucial, especially for SOF teams as they try to be more discreet in their operations and keep a low profile,” Franke explains.
All the U.S. military branches have conducted tests or acquired this type of capability in the last few years. The services have also improved their also procedures to better implement the operation and deployment of passive c-UAS sensors.
At this week's SOF Week 2025 exhibition in Tampa, Florida, DroneShield is showcasing its DroneSentry-X Mk2 software-defined detection and adaptive disruption system, which is a passive-RF counterdrone detection and defeat sensor.
Designed for mobile operations, field expedient pop-up, and fixed-site protection, it can be mounted to standard vehicle roof racks and on military vehicles, surface vessels, and uncrewed mobile platforms to detect and defeat UASs; it can also be permanently installed on standard tripod masts or towers to support protecting facilities and locations.
“It enables our customers to have airspace awareness of any drones or unmanned systems in their airspace. It detects the RF links that those are using and provides that intelligence to our users so that they can decide what action is needed to be taken,” Franke remarks.
He explains that the system provides “essentially an omnidirectional hemispheric coverage” detecting UAS “in 360 degrees and overhead.”
“It is 100% passive. We are basically listening to the RF spectrum for those drone signals, and until you turn on the defeat mechanism, there is no signal emitted, just passively listening,” Franke notes. The system is also fitted with a web-based user interface that enables operators to view real-time analytics of local detection activity with map overlay. Additionally, it offers user-defined options for either automatic or manual disruption.
Although Franke could not provide details about the military branches that currently operate DroneSentry-X Mk2, he states that it “has been fielded by a number of customers across the U.S. and internationally, including government and some non-government entities”.
