the an/aps-20 radar was initially developed during the second world war and had significant limitations to its capability, in terms of its performance at low level over water such that it had difficulty differentiating between sea clutter and actual targets, and short-range. as a consequence, there were attempts to develop an updated aew system for use on royal navy carriers. one of these, which came from the set of proposals from bac, was an updated gannet – in this, bac proposed two spearate schemes: