An older aircraft without ILS receiver cannot take advantage of any ILS facilities at any runway, and much more importantly, the most modern aircraft have no use of their ILS instruments at runways which lack ILS facilities. In attitude and heading reference system pdf of Africa and Asia large airports may lack any kind of transmitting ILS system. Two signals are transmitted on one of 40 ILS channels.
90 Hz, the other at 150 Hz. These are transmitted from co-located antennas. Each antenna transmits a narrow beam. S frequency which corresponds to the selected LOC frequency. S signal is in the 330 MHz range. Statements consisting only of original research should be removed. The glideslope scale is located to the right of the attitude sphere.