What is the TRML-4D? HENSOLDT’s GaN AESA Air Defense Radar

When a Shahed drone appears on a radar screen over Kyiv, the detection chain often begins with a German sensor. HENSOLDT’s TRML-4D — a C-band GaN AESA radar capable of simultaneously tracking over 1,500 targets at ranges up to 250 km — has become one of the most consequential air defense sensors of the current conflict in Ukraine. Introduced at Eurosatory 2018, it was purpose-built for exactly the kind of threat environment Ukraine now faces: mass drone attacks, cruise missile salvos, and supersonic missiles operating across a cluttered, contested airspace.
Product Identity
| Field | Detail |
|---|---|
| Manufacturer | HENSOLDT AG |
| Type | Multi-function air surveillance and target acquisition radar |
| Origin | Germany |
| First unveiled | Eurosatory 2018 |
| Technology | GaN AESA, C-band (NATO G-band) |
| Production status | Series production, active export |
Technical Specifications
| Feature | Value |
|---|---|
| Radar type | GaN AESA (Gallium Nitride Active Electronically Scanned Array) |
| Frequency band | C-band / NATO G-band |
| Measurement dimensions | 4D (azimuth, elevation, range, velocity) |
| Simultaneous tracks | More than 1,500 |
| Instrumented range | 250 km |
| Fighter aircraft track range | >120 km |
| Supersonic missile track range | >60 km |
| Minimum range | <200 m |
| Minimum detectable RCS | 0.01 m² |
| Target types | Cruise missiles, UAVs, fixed-wing aircraft, hovering helicopters |
| Platform | Road-mobile, tactical vehicle-mounted |
Why It Matters
The TRML-4D’s combination of GaN transmit-receive modules with multiple digitally formed beams gives it two critical operational characteristics. First, simultaneous surveillance and fire control from a single aperture — eliminating the need for separate search and track radars. Second, a 0.01 m² minimum RCS detection threshold that encompasses small commercial UAVs, loitering munitions, and low-observable cruise missiles that older systems miss.
In Ukraine, these characteristics have translated directly into operational value. The Bundeswehr-funded TRML-4D transfers since 2022 have contributed to detection and engagement of Russian cruise missiles and Shahed-series UAS that previously evaded less capable radars.
Confirmed Contracts
| Year | Customer | System | Value | Source |
|---|---|---|---|---|
| 2022–2024 | Ukraine (German-funded) | TRML-4D deliveries | Not disclosed | Open source |
| July 2025 | Ukraine (German-funded) | TRML-4D + SPEXER 2000 3D MkIII | EUR 340M+ | HENSOLDT press release |
| Feb. 2026 | ESSI members via Diehl Defence | TRML-4D + maintenance/training | EUR 100M | Janes, HENSOLDT |
Competitor Systems
| System | Manufacturer | Country | Key Difference |
|---|---|---|---|
| EL/M-2084 MMR | Elta/IAI | Israel | S-band, larger platform |
| Ground Master 200/400 | Thales | France | Different frequency architecture |
| TPS-77 | Raytheon/RTX | USA | S-band, US supply chain |
| RAC-3D | Leonardo | Italy | Different architecture |

