Ribri's new Heimdall system blends sound detection and thermal vision to save soldiers from drone attacks.

Chinese manufacturer Ribri Acoustics & Optics presented its new Heimdall man-portable passive drone detection system at the Eurosatory 2026 defense exhibition in Paris. The 6.4 kg Tactical Multi-modal Sensor Cluster utilizes fused acoustic and optical nodes to provide dismounted infantry with early bearing and visual confirmation of low-altitude aerial threats before they enter visual range. This passive sensing approach is designed to counter the deployment of low-radar-cross-section, radio-silent, and fiber-optic-controlled FPV drones in contested frontline environments.

The Heimdall system combines a 48-cell MEMS microphone array offering a 600-meter detection range against small unmanned aerial systems with a tri-mode electro-optical and infrared camera architecture for target verification. The passive sensor configuration operates via TCP/IP and cellular networks within a MIL-STD-810G compliant housing to enable electronic warfare-immune perimeter surveillance without active radar emissions.

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The Heimdall is a lightweight, portable device from Ribri Acoustics & Optics that protects soldiers by using specialized microphones and cameras to quietly listen for and spot incoming drones well before they can be seen. (Picture source: Army Recognition)

On June 19, 2026, the Chinese company Ribri Acoustics & Optics presented its new Heimdall system at Eurosatory 2026, a 6.4 kg man-portable Tactical Multi-modal Sensor Cluster (TMMSC) designed to give dismounted soldiers passive warning against drones before they enter visual range. The Heimdall, named after the Nordic god watching for invaders, combines the HUGIN acoustic node and the MUNIN EO/IR node in one sensor package: the acoustic provides early bearing and classification cues, and the optical provides visual confirmation and track refinement. The system’s mission is not target defeat, but the front end of the C-UAS chain: detection, classification, tracking, and confirmation of FPV drones, Class 2/3 UAS, and larger one-way attack drones such as the Shahed-136.

Its passive fusion approach also allows airspace and ground-perimeter monitoring without radar emission or active jamming, which is relevant for forward units that must maintain silence while still improving local drone warning time. The operational requirement behind the Heimdall is the limited ability of individual soldiers to detect small drones early enough to react. As seen daily in Ukraine, FPV drones and Class 2 or Class 3 UAS can approach at low altitude, use terrain masking and exploit vegetation, buildings, or cluttered terrain to reduce the value of visual scanning and radar-based detection.

Low radar cross-section targets close to ground clutter can be difficult for radar to separate from the background, while RF detection can lose value when drones fly autonomous routes, use pre-programmed navigation, or rely on fiber-optic control instead of a conventional radio-control link. The Heimdall addresses this narrow but important gap by adding a passive sensor layer that can generate an alert before a soldier sees the drone. Its intended use cases include perimeter surveillance, low-altitude warning, and local situational awareness at frontline positions, forward operating bases, infrastructure sites, vehicles, and watch towers. The HUGIN is the acoustic detection node and is built around a 48-cell MEMS microphone array.

The array operates across a 30 dB to 120 dB dynamic range and covers a 150-degree horizontal acoustic sector, making it a directional sensor for a defined approach axis rather than a full 360° perimeter sensor. Its detection range is 600 m (1,950 ft), against FPV or Class 3 drones and more than 5,000 m (16,400 ft) against Shahed-136-type targets. Edge-AI processing at the acoustic node further detects, classifies, and tracks rotary-wing UAS, combustion engines, and loitering munitions in noisy environments. In practical terms, the HUGIN turns rotor noise, engine signatures, and loitering munition sound patterns into a bearing cue that can initiate the alert cycle before the operator has any visual contact. The main operational value of the HUGIN is non-line-of-sight warning.

Using the DJI M350RTK as its reference target, the Heimdall system can detect a Class 3 drone from up to 600 meters away acoustically, and confirm it optically up to 4 kilometers using its zoom camera. (Picture source: Ribri Acoustics & Optics)

Optical sensors need a visual path, and radar performance can be reduced by low-altitude terrain masking, but sound can still reach the microphone array through or around vegetation, buildings, terrain folds, smoke, and darkness. The node does not depend on GNSS, RF control links, or onboard drone emissions, so it remains relevant against fiber-optic-controlled FPV drones, autonomous drones, and pre-programmed flight profiles. This matters most in the last tactical kilometer, where a low-flying FPV drone may become visible only shortly before impact or terminal approach. A 600 m acoustic cue against a small drone gives the unit approximately 30 to 60 seconds of warning, depending on the drone's speed, for search, confirmation, alerting, and possible handoff to an effector.

For its part, the more than 5 km range against Shahed-136-type targets supports earlier detection of louder, larger, combustion-powered threats. The MUNIN is the Heimdall's optical detection and confirmation node, and its function is to reduce ambiguity after an acoustic alert. Acoustic sensors can be affected by vehicles, generators, aircraft, industrial machinery, wind, and other battlefield or urban noise sources, which makes optical confirmation essential before a contact is treated as a drone threat. The MUNIN uses an Edge-AI tri-mode camera architecture with onboard signature recognition and classification, combining HD EO/IR panoramic vision with a telephoto or zoom camera. It can autonomously scan across daytime visual, infrared, and magnified visual channels, then use HUGIN cueing and panoramic detection to lock onto target coordinates.

Consequently, the MUNIN's role is to verify identity, refine the track, and reduce false alarms so that an operator or command system receives a more reliable contact rather than only an acoustic warning. The optical subsystem also separates wide-area search from target identification. The visible panoramic channel has a 7680 × 2160 resolution and a 130° × 42° field of view, giving it broad daylight search coverage across a large sector. The infrared panoramic channel has a 2560 × 512 resolution and a 125° × 26° field of view, adding night and low-light search through thermal contrast. The zoom EO channel has a 1920 × 1080 resolution and a variable 3.2° to 58.3° field of view, allowing the system to move from acquisition to closer identification.

Ribri Acoustics & Optics also showcased the RH20Y, a compact long-range acoustic hailing device that combines directional voice projection with integrated camera and laser systems for surveillance, warning, and security operations. (Picture source: Army Recognition)

Against a DJI M350RTK, used as the Class 3 reference target, the Heimdall's visible panoramic performance reaches 1.4 km, the infrared channel reaches 400 m and the zoom EO channel reaches 4 km. Against Class 2 drones, the corresponding detection ranges are 800 m, 250 m, and 2 km, which shows that the zoom EO channel provides the longest optical confirmation range when line of sight exists, while the panoramic channels support early sector search. The Heimdall’s operating sequence is therefore structured around sensor complementarity. The HUGIN starts the alert cycle by detecting and classifying an acoustic signature across its 150-degree sector, then the MUNIN searches the cued area with panoramic EO/IR sensors and uses the zoom EO channel to confirm and refine the target track.

This division matters because acoustic sensing can warn through non-line-of-sight conditions but cannot provide the same visual identification value as EO/IR imagery, while optical sensing can confirm the object but depends on visibility, line of sight and sufficient target contrast. Ribri's Heimdall, therefore, acts as a passive detection and confirmation node, as its value is highest when connected to local warning systems, C2 networks, or short-range effectors that can act on the confirmed track. The Heimdall’s physical configuration supports man-portable deployment. The sensor cluster weighs 6.4 kg and measures 505 × 326 × 150 mm. It operates from -30°C to +65°C, uses IP65 ingress protection, and meets MIL-STD-810G environmental requirements, giving it the environmental tolerance needed for exposed field use, vehicle mounting, or tower installation.

Networking is provided through TCP/IP and 4G/5G, enabling remote monitoring and connection into wider command-and-control architectures. By including optical detectors, acoustic detectors, Edge-AI processing, and low-SWaP packaging, a single Heimdall can be moved, installed, and networked without the footprint of a larger radar-based C-UAS sensor. In summary, the Heimdall’s tactical feature set includes passive detection, electronic warfare immunity, sensor fusion, fast deployment, modular design, C2 integration, open architecture, all-weather reliability, and detection of low, slow, and small targets. In frontline C-UAS missions, it can cue portable kinetic interceptors by providing warning, direction, classification, and optical confirmation for low-altitude defense.

In maritime and coastal roles, it can support vessel escort, port security, and anti-piracy awareness by adding local passive surveillance around ships, harbor facilities, and coastal sites. In critical infrastructure protection, it can serve as a forward sensor in perimeter networks protecting power facilities, ports, communications nodes, or other fixed sites. At forward operating bases, its passive mode allows continuous surveillance without radar emissions that could attract anti-radiation missiles or reveal coordinates to signals intelligence. As a single Heimdall node only covers sectors rather than a complete perimeter, multiple nodes may be required around a defended site to create a full circular situational awareness, but this latter point depends on the user's requirements.

Also present on the stand, the LPW90Z, a vehicle-mounted LEP searchlight with a range of up to 9,000 m, and the RP41C, a long-range opto-acoustic hailing device delivering communications and warnings at distances up to 2.5 km. (Picture source: Army Recognition)

Written by Jérôme Brahy

Jérôme Brahy is a defense analyst and documentalist at Army Recognition. He specializes in naval modernization, aviation, drones, armored vehicles, and artillery, with a focus on strategic developments in the United States, China, Ukraine, Russia, Türkiye, and Belgium. His analyses go beyond the facts, providing context, identifying key actors, and explaining why defense news matters on a global scale.

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