Scaled Measurements of Instrument-Landing-System Disturbances Due to Large Taxiing Aircraft

It is commonly known that the directional pattern of the instrument landing system (ILS)-localizer antenna system, which constitutes the landing-course information for approaching aircraft, can be disturbed by reflections from large aircraft on the ground. Therefore, airport operators are interested in knowing configurations of landed and taxiing aircraft that lead to such ILS disturbance scenarios. Measurements on a real airport for investigating such scenarios are very cost-intensive and not sufficiently possible due to availability reasons. Therefore, a new scaled measurement setup is presented. Scaling down an aircraft by the factor of 144 requires a scaled ILS-localizer operating at a frequency of nearly 16 GHz, the development and realization of which is presented in this paper. Using this scaled ILS-localizer, measurements with an Airbus A380 and a Boeing B747 are conducted showing the feasibility of the scaled approach. Several configurations are shown where those aircraft lead to interferences of the ILS, exceeding allowed tolerances. A comparison of the reflection behavior of both aircraft shows only slight differences. Additionally, this paper presents the derivation of the bistatic radar cross section of both aircraft to be applicable to scenarios with arbitrary ILS patterns.