Perspective Study Of Building With Simple Structure Based On The Characteristics Of Radio Wave Propagation

The perspective of building with simple structure refers to obtaining the corresponding experimental data through certain measurement means outside the building,and obtaining the geometric distribution of the building through the analysis and processing of the data.It is of great significance to obtain accurate geometric structure of buildings in various scenarios such as anti-terrorism rescue,military operation,emergency relief and so on.In this paper,based on the propagation law of electromagnetic wave in buildings,three methods of solving the propagation path of transmitted electromagnetic wave are analyzed,and the feasibility of extracting the reflection coefficient of buildings by non-destructive method is studied.The electrical parameters of the marble are obtained by means of particle swarm optimization(PSO)and measured reflection coefficient.Based on the measured multi-path time delay data,the method of obtaining the building's exterior size is studied.The main research results of this paper are as follows:1.The solution of wave equation of electric field is derived from maxwell's equations.The electromagnetic wave in the graphic interface and the propagation rules of layered medium is analyzed.The dependence of electromagnetic wave reflection coefficient and transmission coefficient on the different incident angle,different polarization modes and different electrical parameters are studied in frequency domain.The research content of this chapter provides theoretical basis for the establishment of transmission model and the extraction of building reflection coefficient.2.The propagation law of electromagnetic wave in buildings is investigated.Based on the Fermat principle,three possible transmission paths of electromagnetic wave through buildings are studied according to the different transmitting and receiving antenna positions.In this paper,the prediction of power coverage and path loss in buildings is examined based on the accurate propagation path of transmitted electromagnetic wave.Finally,the results of power coverage and reception delay under different conditions are compared with those obtained by the approximate method.3.Based on the basic theory of ultra-wideband(UWB)system,the basic principle of measuring the reflection coefficient of medium in ultra-wideband system is investigated.The reflection and echo signals of several media are measured and the results in time and frequency domain are presented.Based on the results of several sets of measured data,the feasibility and limitation of using time window separation method to obtain reflection coefficient are analyzed.According to the basic principle of particle swarm optimization(PSO),the inversion results of electrical parameters under different conditions are simulated,and the subsequent inversion of measured electrical parameters are prepared.The electrical parameters of typical building material(marble brick)are obtained by combining the theoretical research with the measured results.4.Combined with the above contents,the inversion scheme of building geometric structure is present.The input and output data of the inversion program are defined.The inversion results of building structures with different building information and different transmitting and receiving antenna positions are also simulated.The feasibility of extending the inversion method of single room geometry structure to the inversion of multi-room and multi-floor buildings is examined in this paper,and the similarities and differences between the two cases are pointed out.The treatment of forward transmission problem under different conditions is given.