With the High Seas Firings of the Royal Dutch Navy in November 2003 in the Atlantic near Madeira, a new guidance principle was demonstrated to the world: X band Mid Course Guidance with Sampled Data Homing, commonly called ICWI. The Dutch LCF, German F124 frigates and soon the Royal Danish Iver Huitfeldt class, can each bring a broadside to bear upon many simultaneous air targets, equivalent to the capability of multiple US Arleigh Burke class destroyers. This is achieved on a displacement of only 6000 tons.
ICWI is a guidance principle based on semi active homing. With semi active homing, the target is tracked and illuminated by radars on the ship. The missile tracks the target with its purely passive radar and homes in on the reflected energy. As only the target is illuminated, the missile has less trouble sorting out the target from its surroundings, compared to an active missile. The great advantage of this principle is that large amounts of illumination power can be brought to bear on the target to prevent jamming and misleading.
For successful operations and minimizing collateral damage, the "man in the loop" wisdom and control capability of ICWI is becoming an essential requirement when operating in an littoral environment.