Influences of 3D Aircraft Model to ILS Localizer

This paper is concerned with a numerical simulation of ILS subsystem Localizer (LOC) which provides the guidance in the horizontal position of an aircraft for the runway center line. The LOC emits two types of signals, that is, carrier wave and sideband waves modulated by a 90 Hz and a 150 Hz tone. The performance of the LOC is given by the difference in the depth of the modulation (DDM). However, their signals are influenced by obstacles, such as large hanger, terminal buildings and aircraft. They result in the DDM errors. In this paper, the authors analyze the multipath interferences caused by aircraft to LOC whose type is one frequency LOC (1fLOC). A simplified ray tracing method is introduced, and 3D aircraft model is used for numerical simulation. It is discussed how scattered waves from aircraft influence to the LOC specifications.