I.L.S. far-field and radio environment monitoring

Experimental investigations into the techniques of far-field ocalizer and glide-path monitoring for Category III I.L.S. installations are described. The results of monitoring at an operational airport over an extended period are presented. Two novel techniques are briefly described: (a) a system of spaced aerials for monitoring beam-bend noise, and (b) an independent side-band receiver for the detection of radio interference.