Study On The Analysis And Verification Of Radiowave Propagation Based On The Two-Way Parabolic Equation In Obstacles Environment

In the military field that the information warfare and the electronic war are intensified,the study of the radio wave propagation in the complex environment is the basis for the evaluation of electromagnetic environment and electromagnetic situation.It is not only the foundation for the safe and reliable prediction of battlefield communications,but also the premise of the assessment of the electronic countermeasure(ECM)and electronic counter-countermeasures.In recent years,the parabolic equation(PE)method has gradually become the most commonly used method of the tropospheric wave propagation research.When the terrain fluctuation is obvious,the two-way PE is the most accurate method.Therefore,according to the two-way parabolic method,this thesis mainly focuses on the research of the radio wave propagation in the obstacles environment and the verification and modification of the two-way PE method itself by the method of the moments(MoM).The main contents of the thesis include the derivation of the two-way parabolic equation(PE)in the obstacle environment,the verification of the PE by the MoM and the practical application of the PE method.The three parts are divided into five aspects.1.Firstly,focusing on the radio wave propagation in complex environment,this thesis mainly analyzes the basic principle and calculation method of two-way PE method,which lays a theoretical foundation for solving the problem of the radio wave propagation in obstacle environment,as well as points out the related problems existing in PE method at present.2.In order to verify the accuracy of the two-way PE method and the new algorithm in the obstacle environment.Applying MoM to verify the calculation accuracy of the radio wave propagation is proposed at the short distance in the complex environment.The electronic field integral equation(EFIE)for the horizontal polarization and the magnetic field integral equation(MFIE)for the vertical polarization under the circumstance of the conductor obstacle are deduced,and the calculation formula of the MoM is given.At the same time,the PMCHW equation using in the medium obstacle is deduced,and this calculation method under different polarization in the obstacle environment is given in this thesis.These methods provide an effective means for the accurate verification and the modification of the two-way PE.3.Aiming at the problem that the medium parameter of the obstacle is different with the ground,and the accuracy of the calculation is limited by the inclination of the undulating terrain.For the research of the radio wave propagation when the obstacle is the ideal conductor,A new method based on the two-way PE is put forward.In the process of the algorithm,the historical paths of all the wave sources are recorded,and the phase of the calculation fields of the two-way PE is corrected according to the specific path of the wave.In the stepping process,the boundary conditions of the obstacle surface under different polarization are re-processed.The staircase model is also improved.Finally,the MoM is used to verify the improvement of the accuracy of the original parabolic method by the examples analysis,which verifies the effectiveness of the new method.4.This thesis also mainly focuses on the research of the radio wave propagation when the obstacle is homogeneous medium.Considering the existence of the transmission field inside the obstacle,the field inside the obstacle may influence the spatial field.A new two-way PE algorithm based on the domain decomposition is presented.This method divides the obstacles and the ground into different zones.According to the difference of the media parameters inside and outside the obstacle,the phases of calculation fields in the different zones are modified to realize the unity of the field calculation in the space.Finally,the accuracy and effectiveness of the new algorithm in obstacle environment is verified,which lays the foundation of the radio wave propagation in real complex environment.5.In order to meet the needs of ECM force equipment,this thesis integrates the research content and applies into the specific shortwave and ultrashort-wave communication equipment.Through the MATLAB platform,the research content is programmed into a set of field calculation software according to the PE method.And the logarithmic periodic antenna is added into the calculation software.The jamming field strength analysis software is achieved in obstacle for communication countermeasure equipment with the logarithmic periodic antenna.This software plays an important value to improve the operation effectiveness of the ultrashort wave electronic countermeasure equipment.