Horizon-class frigate

The primary problem was that of differing requirements: France wanted anti-aircraft warfare (AAW) escorts for its aircraft carriers, but only a limited range was necessary due to the self-defence capability of the French Charles de Gaulle.

Italy too required only close-range capabilities, as in its home waters of the Mediterranean Sea the ships would operate under Italian Air Force cover or escorts for its aircraft carrier Cavour.

The Royal Navy, however, required more capable ships which could throw a large defensive "bubble" over a fleet operating in hostile areas.

[12] The compromise that largely solved this problem was the adoption of a standard radar interface, which allowed France and Italy to install the EMPAR multi-function passive electronically scanned array radar and the UK to install the more capable SAMPSON active electronically scanned array radar—the SAMPSON radar has a higher data rate and an adaptive beam that allows a greater ability to track multiple targets, long-range detection of low-RCS targets, a lower false-alarm rate, and overall higher tracking accuracy.

[14] The Financial Times summarised the main disagreements between the partner countries:[15] The resulting Type 45 destroyer is armed with the PAAMS missile system and has benefited from investment in the Horizon project.

[1] On the Italian units, the three cannons will be upgraded to the 76 mm/62 Super Rapid Multi Feeding David/Strales version with the capacity to use the DART guided projectile in the anti-missile role.

Italian Caio Duilio