Electromagnetic Signal Simulation Of Instrument Landing System Based On GIS

In the airport terminal area, Instrument Landing System (ILS) is an importantnavigation equipment leading aircraft precisely to approach and land.ILS plays animportant role in making sure an aircraft approach and land safely under complexweather conditions like low cloud and low visibility.The reason why ILS has such amagical and powerful function relies on its electromagnetic wave including Localizersignal and Glide slope signal. These to signals cross one another and form the“electromagnetic tunnel” from air to the threshold. Even in bad weather conditions, this"electromagnetic tunnel" will be able to lead the aircraft to the runway and landingsafely.Based on this, this paper is dedicated to research the ILS electromagnetic signalcomprehensively and systematically. Firstly, this paper simulates the Localizer antennaand Glide slope antenna. In the order of single antenna to array antenna, this papercarries out3D modeling for Localizer antenna、Glide slope antenna and Marker antenna,then writes programs basing on the idea of uniform slices sampling in the MATLABcircumstance and realize simulation of Localizer signal and Glide slope signal in freespace, which makes the invisible electromagnetic guided signal visible. When modelingLocalizer antenna and Glide slope antenna, this paper applies the idea of equivalentnetwork to solve the current distribution on the antenna, then uses the moment methodto solve Maxwell equation and obtains the antenna radiation characteristics in space. Inthe process of modeling Marker antenna, this paper applies coupled Hallen equation tosolve the current distribution of Yagi antenna, and then uses the method of moments tosolve spatial radiation characteristics of the Marker antenna. On this basis, this papergenerates spatial data points which will correspond respectively to Localizer signalmodel and Glide slope model then establishes spatial topological relations of these datapoints in accordance with the idea of uniform slice sampling. Finally basing on the GISplatform, this paper applies class polar radius substitution method based on sphericalcoordinates to makes a fusion of spatial point data and terrain elevation data and realizes Localizer signal simulation and Glide slope simulation under the real geographicalenvironment.