The ILS system, developed just prior to the start of World War II, used a more complex system of signals and an antenna array to achieve higher accuracy. This requires significantly more complexity in the ground station and transmitters, with the advantage that the signals can be accurately decoded in the aircraft using simple electronics and displayed directly on analog instruments.[1] The instruments can be placed in front of the pilot, eliminating the need for a radio operator to continually monitor the signals and relay the results to the pilot over the intercom.