DSEI 2025 – SEOSS 400, Rheinmetall fire control sensor for the 130 mm tank gun

Rheinmetall started developing the 130 mm tank gun and its ammunition some years ago. Although no decision on a new calibre for western MBTs has been taken yet, the development is advancing, and considering the effective range of the new weapon the EMES-15 sight used on the Leopard 2 is not sufficient. At DSEI the Düsseldorf-based group unveiled the SEOSS 400, a fire control sensor specifically designed for the potential future calibre

The Rheinmetall portfolio includes several SEOSS, the acronym standing for Stabilized Electro-Optical Sighting System. The SEOSS 200 and SEOSS 300 are both two-axis stabilised systems. The smaller one features a 1920×1080 CMOS colour sensor with a continuous zoom providing a field of view from 2° to 54°, a x16 electronic zoom being also available, a 640×512 cooled MWIR thermal sensor with a 2° to 27° continuous zoom. A Class 1 eye-safe laser rangefinder allows to measure target distances up to a maximum range of 20 km. No detailed data are available for the bigger SEOSS 300, but this should have even better performances, the system being fitted to Rheinmetall’s Lance turret installed on Australian Boxers and on Hungarian Lynx.

To be able to hit a target with a penetrator round at 5 km distance or more, not only the identification range must be higher than that of the existing systems, which are around 4 km, which obviously also increases detection and recognition ranges, but also sight stabilisation must be considerably improved. Range increase is obtained with the adoption of bigger sensors; both day and night channels exploit 5 megapixels (MP) arrays, which usually means 2592×1944, which is over 2,5 times more than today day CMOS sensors, and even more when talking thermal. Moreover, the two images can be fused to improve detection when hot spots such as running engines are hiding behind nature. According to Rheinmetall sources, identification range is more than 6 km, which means more than the effective range for current 130 mm rounds.

However, this is not sufficient if stabilisation does not allow an improved angular accuracy; here the three-axis stabilisation comes into play, the SEOSS 400 having a 0.03 mrad angular position report accuracy versus 0.1 mrad of previous SEOSS. These performances were verified installing the new SEOSS on a Leopard 2, travelling at 40 km/h. The SEOSS 400 was designed to cope with very harsh conditions, and it can cope with fording operations up to 4 metres depth.

The SEOSS 400 is a wholly new development, and the system hosts all subsystems, such as the computer, inside its case. The very high-resolution image helps of course automatic identification by artificial intelligence algorithms, which shifts the target to the automatic tracking system, the rangefinder providing distance, dynamic lead giving the ballistic equation, all in an automated manner also against moving targets, the man in the loop having only to authorise fire. This considerably reduces the gunner workload and increases first hit probability.

The SEOSS 400 screen gets information from many sources, such as the battle management system, the laser warning receiver, and other sensors. Markers appear on the screen and can be assigned to the targeting system by clicking on them.

The SEOSS 400 is compatible with future system architectures, and especially those of the two European programmes in the MBT arena, the Main Ground Combat System (MGCS) and the Main Armoured Tank of Europe (MARTE).

It features seamless network connectivity and is designed for being integrated both on manned and unmanned systems and is ready for a spiral improvement. This might include multi-mode tracking, modular sensor expansion, enhanced ballistic algorithms and extended fire control computing, including beyond line-of-sight (BLOS) capabilities, an issue that has emerged strongly in recent times, with Leonardo and MBDA unveiling their solutions for giving modern MBTs an indirect fire capacity. Beside MBT integration, the new SEOSS 400 is also considered for air defence platforms.

Graphic courtesy Rheinmetall, photos by P. Valpolini