The S1850M is a long range radar with a digital antenna array for wide area search in elevation. The S1850M is produced by BAE Systems Integrated System Technologies (formerly AMS UK) and Thales. It is a modified version of the Thales Nederland SMART-L radar. The S1850M is advertised as being capable of fully automatic detection, track initiation and tracking of up to 1,000 targets at a range of 400 kilometres (250 mi). It is also claimed to be highly capable of detecting stealth targets, and is able to detect and track outer atmosphere objects at short range, making it capable of forming part of a Theatre Ballistic Missile Defence system.
The contract for initial production of the S1850M was signed in 2001; 2 for the UK, 1 for France and 1 for Italy, with a common prototype based in Toulon. In 2005 a follow-on contract was signed for 5 more for the UK, 1 more for France and 1 more for Italy. A further developed version of the Smart-L is being installed on ships by the Royal Netherlands Navy, which is an updated version of the current SMART-L radar called the SMART-L-EWC (Early Warning Capability) Radar. This has a greater search radius, capable of detecting ballistic missiles and has a tracking range of 2000 km for ballistic missile defence and 480 km for air defence. SMART-L EWC is a programmable PESA radar which is characterized by full flexibility. Additional capabilities can be introduced during lifetime according to customer needs. This makes the radar future proof in case of evolving requirements.
In all its current applications the S1850M is the long range radar (LRR) component of the Principal Anti Air Missile System. On the Type 45 destroyers it is paired with the SAMPSON multifunction radar, on the Horizon ships it is paired with the EMPAR multifunction radar.
On 11 February 2009, Thales indicated that the S1850M radar will be fitted on the Royal Navy's Queen Elizabeth-class aircraft carrier.