Electromagnetic Environment Analysis Of Instrument Landing System And Test System Integration

Instrument Landing System (ILS) is an important navigation equipment which can lead aircraft precisely to approach and land, and it has been widely used all over the world. ILS plays an important role in guaranteeing the aircraft approach and land safely under the complex weather conditions such as low cloud and low visibility, so the more strict electromagnetic environment requirement is needed. However, with the development of the city and science, more and more buildings, factories, electric railway and high-voltage lines are newly built surrounding the airport, producing all sorts of positive and active electromagnetic harassment. The electromagnetic environment of ILS is deteriorating constantly, which poses a serious threat to flight safely. So, it’s important to analysis and test the electromagnetic environment of ILS. And it can ensure the flight safety and improve the compatibility of the civil aviation and other system.This paper is dedicated the research of the electromagnetic environment of ILS comprehensively and systematically. Firstly, this paper analyzed the composition of the electromagnetic environment of ILS, and the various kinds of electromagnetic interference(EMI) is divided into two categories:passive and active EMI. Secondly, according to the binary antenna array theory and antenna mirror theory, this paper completed the mathematical modeling of the ILS antenna array for the ideal condition and the single multipath effect condition respectively. Thirdly, a radiation test of pantograph arc was carried out near the phase insulator, overlap and general position of Dazhou-Chengdu railway. And the radiation at 10m was acquired. The electromagnetic compatibility is predicted based on the test results when the electric railway crossed the glide path vertically. And the EMI caused by the pantograph arc was evaluated by the protection ratio. Finally, an electromagnetic environment test system was designed based on the virtual instrument technology. The hardware of the system is combined with antenna, spectrum analyzer, USB-GPIB, USB-DAQ and PC. The system used the interactive interface design on LabWindows/CVI to realize the unified management of test project, and also accomplished the control of spectrum analyzer and the design of data acquisition module respectively by VISA,SCPI and NI-DAQmx. At last, a test was conducted in the laboratory to verify the validity of the test system.