Influences of scattered field caused by buildings to ILS localizer in Airport

This paper is concerned with influences of scattered field caused by buildings to instrument landing system (ILS). The localizer (LOC) which is one of ILS subsystem, plays an important role to provide guidance in the horizontal position of aircraft. The LOC emits signals with a varying modulation. The performance of the LOC is obtained by the difference of depth of modulation (DDM) whose values are distorted by the multipath caused by scattering objects, such as building and aircraft. In this paper, we provide a solution for analyzing electromagnetic fields in airport. Firstly, we review the principle of the LOC system. Then, we propose a numerical method based on the ray tracing method (RTM) in three dimensional propagation environment. In the numerical simulation, we show field distribution and the value of DDM. Finally, we discuss the influences of scattered field caused by buildings in an airport.