Analysis of signal strength attenuation of localizer at an airport in western China

Localizer is an important part of the instrument landing system(ILS), providing the horizontal guidance signal for aircraft precision approach. If the signal coverage of the localizer is not qualified, it may cause the restricted use, or it may cause the unavailability of the localizer and lead to the flight cannot land. In this paper, we combine the results of Flight inspection and obscuration angle plotting to find out what really cause the signal to be affected, and then analyzing whether they intrude into the Fresnel zone of the transceiver line through signal propagation theory, and calculate the signal attenuation value. It also provides an idea to analyze the signal of airport radio stations.