Rheinmetall and HENSOLDT Just Gave a Gun-Based Air Defence Battery Eyes That Do Not Glow

The most dangerous moment for a ground-based air defence battery is not when it shoots. It is when it looks. Radar emissions are an address, and modern anti-radiation weapons read addresses fast. During the German Air Force’s Timber Express 2026 exercise in August, Rheinmetall Air Defence and HENSOLDT demonstrated a way around that problem: they wired HENSOLDT’s Twinvis passive radar into Rheinmetall’s Skymaster command and engagement system and a Skynex air defence battery.

What was demonstrated

Track data generated by Twinvis was passed over NATO’s Link 16 datalink into Skymaster, which fused inputs from active radars, the passive sensor and electro-optical sources into a single air picture and ran engagement decisions from it. According to the joint statement from both companies, Twinvis showed strong performance in detecting and tracking airborne targets.

The companies say the same architecture extends to fixed Skynex sites, mobile Skyranger turrets and counter-UAS products such as Skyspotter. The goal is not one integration; it is a networked air defence architecture spanning static, mobile and drone-defence configurations.

How passive radar works

A conventional radar transmits energy and listens for the echo. It is precise, and it is loud. Passive radar inverts the arrangement. Twinvis transmits nothing. Instead it exploits signals already saturating the environment — FM radio, digital audio broadcasting (DAB) and terrestrial digital television (DVB-T) — as illuminators, comparing the reflection off an aircraft against the direct signal to extract range and velocity.

Because the sensor never emits, it cannot be detected electronically, cannot be jammed in any conventional sense, and cannot be targeted by weapons that home on radar emissions. It is, in the most literal sense, a sensor that does not glow.

Why this changes the emissions problem

Passive radar alone has real limits. Coverage depends on the geography of the transmitter network, low-altitude and rural gaps are common, and measurement precision does not match a modern active array. The gain appears when passive tracks are fused with active ones.

In that architecture a battery can keep its active radar silent, run its air picture off the passive sensor, and light up only for the seconds an engagement actually requires. That compresses the interval during which the battery is findable — the single greatest vulnerability of ground-based air defence, and one the war in Ukraine has demonstrated repeatedly and expensively.

What Timber Express tests

Exercises like this measure interoperability rather than raw performance. Two systems that look compatible on paper can fail in the field over milliseconds of latency or mismatched track correlation. The critical success criterion here was whether Skymaster could merge a Twinvis passive track and an active radar track as the same object rather than two — track correlation being one of the harder engineering problems in networked air defence.

The portfolio context

Skynex uses 35mm cannon with programmable air-burst ammunition, which scatters sub-projectiles near the target and removes the requirement for a single precise hit against small manoeuvring drones. It has seen combat use in Ukraine. Skyranger applies the same logic in a turret that moves with mechanised formations. Adding Twinvis gives the entire family the option of receiving target data without switching on a transmitter of its own — most valuable precisely for the mobile systems, whose greatest weakness is broadcasting their position while on the move.