In aviation, the instrument landing system is a precision radio navigation system that provides short-range guidance to aircraft to allow them to approach a runway at night or in bad weather. In its o
View of the primary component of the ILS, the localizer, which provides lateral guidance. The transmitter and antenna are on the centerline at the opposite end of the runway from the approach threshold. Photo of Indra's Normarc localizer, taken at the runway 06R of the Montréal–Trudeau International Airport, Canada.