The four De Zeven Provinciën-class frigates are air-defence and command frigates in service with the Royal Netherlands Navy (Koninklijke Marine). This class of ships is also known as "LCF" (Luchtverdedigings- en commandofregat, air defense and command frigate). The ships are similar to the German s in role and mission. Antiaircraft warfare These ships were optimized for anti-aircraft warfare and command. For this role the ships are equipped with an advanced sensor and weapons suite. The primary sensors for this role are the long range surveillance radar SMART-L and the multifunction radar Active Phased Array Radar (APAR). The SMART-L and APAR are highly complementary, in the sense that SMART-L is a D band radar providing very long range surveillance while APAR is an I band radar providing precise target tracking, a highly capable horizon search capability, and missile guidance using the Interrupted Continuous Wave Illumination (ICWI) technique, thus allowing guidance of 32 semi-active radar homing missiles in flight simultaneously, including 16 in the terminal guidance phase. The primary anti-aircraft weapons are the point defence Evolved Sea Sparrow Missile and the area defence RIM-66 Standard Missile (SM-2) Block IIIA. The Mk 41 Vertical Launch System is used to house and launch these missiles. 32 Evolved Sea Sparrow Missile and 32 Standard Missile SM-2 Block IIIA are carried. Ballistic missile defence The Royal Netherlands Navy (RNN) investigated the use of these ships for the role of ballistic missile defence (BMD). During tests carried out by in the Pacific Ocean near Hawaii, experimental modifications to the SMART-L to allow even longer range were proven. A study by the RNN, the Netherlands Defence Material Organization, Thales Nederland, Raytheon Missile Systems, Johns Hopkins University Applied Physics Laboratory, and Lockheed Martin was conducted to establish the feasibility of modifying the De Zeven Provinciën class to provide it the capability to intercept ballistic missiles. In particular, the study examined the feasibility of integrating the SM-3 Block IB missile with the SMART-L and APAR radars. The study concluded that – with certain modifications to the SMART-L and APAR, as well as to the ship's Combat Management System and the missile itself – BMD with the De Zeven Provinciën class could be achieved. During a 2015 very large NATO military exercise the BMD capabilities were proven, the sensor suite discovered ballistic targets, and the ship destroyed them using both its own surface-to-air missiles, as well as using a U.S. Navy