Reliable acoustic drone detection
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Not in sight, but within hearing range: detecting and locating drones thanks to intelligent sensor data fusion
Fraunhofer IDMT in Oldenburg has developed an intelligent sensor solution that detects drones even outside the line of sight. The acoustic detection technology can be combined with radar, camera, and lidar to form a complete system.
Oldenburg, November 13, 2025. When a drone (also known as an unmanned aerial system, or UAS) approaches a security-critical area without permission, it poses a potential threat. In some cases, optical sensors, radio, and radar are disrupted by terrain, weather, or technical measures and cannot reliably detect a drone.
The Fraunhofer Institute for Digital Media Technology IDMT in Oldenburg has developed an integrated acoustic sensor solution for drone detection and localization. In view of the increasing threat posed by unmanned aerial vehicles in security-critical areas, the system fills a crucial gap: it “hears around corners”. Acoustics can be combined with radar, camera, and lidar to form a robust sensor data network. Unlike purely optical and radar-based methods, which rely on line of sight, the technology enables drone operations to be detected even in built-up or forested areas.
Since 2016, the Oldenburg Branch for Hearing, Speech and Audio Technology has been advancing the acoustic detection of drones in the publicly funded joint projects AMBOS (BMBF) and ALADDIN (H2020). Twelve partners participated in the AMBOS project under the leadership of the Fraunhofer Institute for Communication, Information Processing and Ergonomics FKIE. For ALADDIN, 18 partners from nine European countries joined forces, including the CS Group as project manager. The algorithms and system components were continuously refined in numerous internal projects. Today, in addition to easily integrable algorithms for the detection and localization of UAS, researchers can also rely on a fully integrable system solution.
Fiber-optic-controlled drones or autonomous flying objects often remain hidden from radio reconnaissance, while high-resolution radar and camera systems require high costs and energy-intensive computing power. The acoustic solution from Fraunhofer IDMT, on the other hand, operates with low energy consumption, enabling autonomous operation with rechargeable batteries. The ability to wake up additional sensor components after acoustic contact also offers advantages. The technology can achieve 360° coverage. Depending on the noise environment, the detection and localization ranges are between 50 and 200 meters, with a temporal resolution of one second. An extension to other acoustic events, from vehicles to gunshots, is conceivable. Thanks to their high availability, the acoustic sensors can be deployed across large areas.
“With our acoustic technology, we offer an inexpensive and low-maintenance addition to existing drone detection systems,” explains Christian Rollwage, Head of “Audio Signal Enhancement” at Fraunhofer IDMT.
The target customers for the new technology are primarily companies in the defense and security sector that are already developing drone detection systems based on radar, optics, or lidar, as well as system integrators who want their own sensor technology and drone manufacturers who want to detect signals from the air.
Fraunhofer IDMT has published a video on its YouTube channel about the detection and localization of drones: https://youtu.be/cSuV9xzcgXY
Hearing, Speech and Audio Technology HSA at Fraunhofer IDMT
in Oldenburg
Founded in 2008 by Prof. Dr. Dr. Birger Kollmeier and Dr. Jens-E. Appell, the Fraunhofer Institute for Digital Media Technology IDMT’s Branch for Hearing, Speech and Audio Technology HSA stands for market-oriented research and development with a focus on the following areas:
- Speech and event recognition
- Sound quality and speech intelligibility
- Mobile neurotechnology and systems for networked healthcare
With in-house expertise in the development of hardware and software systems for audio system technology and signal enhancement, the employees at the Oldenburg site are responsible for transferring scientific findings into practical, customer-oriented solutions.
Through scientific cooperation, the institute is closely linked to the Carl von Ossietzky University, Jade University of Applied Sciences, and the University of Applied Sciences Emden/Leer. Fraunhofer IDMT is a partner in the “Hearing4all” cluster of excellence and in the Collaborative Research Centre “Hearing Acoustics”.
Further information on www.idmt.fraunhofer.de/hsa
Contact for the media:
Christian Colmer
Head of Marketing and Communication
Fraunhofer-Institute for Digital Media Technology IDMT
Oldenburg Branch for Hearing, Speech and Audio Technology HSA
Marie-Curie-Str. 2
26129 Oldenburg
Phone +49 441 80097-312
christian.colmer@idmt.fraunhofer.de
http://www.idmt.fraunhofer.de/hsa
Fraunhofer-Institute for Digital Media Technology IDMT
Oldenburg Branch for Hearing, Speech and Audio Technology HSA
Marie-Curie-Str. 2
26129 Oldenburg
Phone +49 441 80097-312
christian.colmer@idmt.fraunhofer.de http://www.idmt.fraunhofer.de/hsa