Test And Analysis Of Radio Frequency Compatibility Between Microwave Landing System And C_N-band Satellite Navigation

The Microwave Landing System(MLS)is an all-weather precision approach landing system that broadcasts time reference scanning beam(TRB)based airborne guidance signals on 5,030.4MHz～5,150.0MHz to provide high precision and reliable approach guidance services to MLS-equipped aircraft in its signal coverage sector.The adjacent C_N-band,5,010MHz to 5,030 MHz,was allocated for satellite navigation downlink signals at the World Radio Communications Conference(WRC)in 2000.The two systems operate in close frequency bands,so the radio frequency compatibility of them must be tested and evaluated.In this thesis,based on an in-depth study of the MLS signal system,a step-by-step study of theoretical analysis and test techniques for the radio frequency compatibility of MLS and C_N-band satellite navigation is carried out,with the following main work.Firstly,according to the relevant standards in Annex 10 to the Convention on International Civil Aviation-Aeronautical Telecommunications(Volume I)issued by the International Civil Aviation Organization(ICAO),simulations of the MLS azimuth guidance signal,elevation guidance signal,data word signal and the MLS full-cycle baseband signal composed of the above sub-signals were carried out.On this basis,various MLS signal quality parameters,including power density distribution,are studied in depth.Secondly,in order to complete the radio frequency compatibility analysis between C_N-band satellite navigation and Microwave Landing System.The interference for C_N-band satellite navigation downlink signal from several in-view space stations on MLS service is evaluated through the calculation of the Power Flux Density(PFD)values.Simulation analysis of the interference for MLS DPSK-data word signal and scanning signal on C_N-band satellite navigation signal is based on the Spectral Separation Coefficient(SSC)and equivalent Carrier-to-Noise Ratio(ECNR)methodologies.The required separation distances and some other compatibility coordination recommendations to avoid harmful interferences are finally summarized.Thirdly,a ground testing scheme for the radio frequency compatibility of these two systems in the airport runway environment is presented,including the setting of signal acquisition points and the specific signal acquisition process.The measured data acquired during the tests are analyzed to verify the correctness of the simulation analysis.The MLS signal quality flight test procedure is also introduced based on the Federal Aviation Administration(FAA)technical standards directive 8200.1D,U.S.Standard Flight Inspection Manual.