Thales has delivered the first of the company’s Sentinel-U radar electronic support measures to equip the Marine Nationale’s ‘Suffren’ class nuclear-powered attack submarines.
The French Navy is acquiring six ‘Suffren’ class boats. Three vessels, namely Suffren, Duguay-Trouin and Tourville, have been launched with the first two commissioned. A further three are under construction with four conventionally-powered versions of the submarine equipping the Koninklijke Marine (Royal Netherlands Navy). The Sentinel-U, which is equipping the ‘Suffren’ class, is one member of Thales’ Sentinel family of Radar Electronic Support Measures (RESM). The Sentinel-H variant is equipping the French Navy’s forthcoming ‘Amiral Ronarc’h’ class frigates.
RESMs are particularly important for submarine survivability. A former French Navy submariner shared with Armada that submarines routinely deploy a very small RESM antenna just above the water before surfacing. The presence of a Maritime Patrol Aircraft (MPA) in the submarine’s locale is a particular concern. These aircraft often use X-band (8.5 gigahertz/GHz to 10.68GHz) airborne surveillance radars to locate submarine periscopes. The RESM antennas tend to be designed to produce as small a radar cross section as possible to these radars. This helps preserve the submarine’s discretion. If such a radar is detected by the RESM, the submarine can have as little as 20 minutes to dive and escape the area. Once it detects a submarine, the MPA will begin using its magnetic anomaly detector and sonobuoys to locate the boat before launching torpedoes.
Sentinel deliveries
Thales officials shared with Armada that the Sentinel-U has been delivered to Naval Group, which is building the ‘Suffren’ class with an expected in-service date of 2025 for the RESM. It is unclear if the Sentinel-U will only outfit new SSNs or will be retrofitted onto the three boats already launched. Open sources say the existing ‘Suffren’ class submarines use an electronic warfare system called Nemesis. Almost no details appear to exist in the public domain regarding this system, although it is likely that Nemesis is a Thales product. The company remains the incumbent supplier of Electronic Warfare (EW) systems to the French Navy.
The officials continued that the Sentinel family performs fully digital processing of Signals-of-Interest (SOIs) across wavebands of two gigahertz/GHz to 18GHz. The system can be extended downwards to 50 megahertz and upwards to 40GHz if desired by the customer. Regular software updates are planned as Sentinel moves through its service life. These updates include the additional of cognitive EW algorithms intended to lighten the operator’s workload through the rich analysis of SOIs. Sentinel variants are also likely to equip the French Navy’s future Porte-Avions de Nouvelle Génération (New Generation Aircraft Carrier) which replaces the Charles de Gaulle. The latter is the navy’s current aircraft carrier and flagship.
The full mission fit for the Sentinel-U includes the submarine’s EW operator console and accompanying equipment cabinets. The electronic support measure links to two Safran Series-30AOM/SOM attack and search optronics mast which are both equipped with integral RESM antennas. Thales officials continued that an ashore EW system complements the Sentinel-U. This can be used for the interpretation of unknown SOIs collected by the RESM and for the system’s overall management. With the Euronaval exhibition in Paris on the horizon between 4th and 7th November, more details regarding the Sentinel family may be forthcoming at this event.
by Dr. Thomas Withington
