Research On Modeling Of Scattering Echo And Characteristics Of Time And Frequency Domain From Low-Observable Targets

With the development of electromagnectics,electromagnetic scattering of low-observable targets attract more and more attention.Rapidly and precisely analyzing the Radar Cross Section(RCS)of these targets have wide range of applications in the fields of radar detection.The main purpose is to study characteristics of targets in frequency domain rather than time domain in the research of stealth and anti-stealth technology.If you can analyze it in both frequency and time domain,the target detection performance will be improved.In this paper,we study the RCS of low-observable targets combined with a project.It mainly includes the following aspects:First of all,the paper has accomplished establishing model of low-observable targets by Hyper Mesh,which is a Finite Element Analysis(FEA)preprocessing software.It includes cleaned up methods and meshing repaired work.The cleaned up methods is to raise the quality for these targets,and the meshing generation is the precondition of calculate RCS of these targets by electromagnetic simulation software.Then the steps of FEA's preprocessing and some practical meshing methods are summarized.And then we analyze RCS of different targets according to Feko,which is a electromagnetic simulation software,by learning the basic principle related concepts of electromagnetic calculation methods based on Feko,the most algorithms for different targets and different frequency bands are summarized.Finally,target modeling and RCS calculation provide a data basis for subsequent work.Then the echo modeling has been accomplished.This paper obtained the radar echo signal mathematical model by theoretical analysis and radar equation,the final signal mathematical expression is completed by the parameters establishing model.Secondly,analyzing the different target echo with time or frequency domain,and the specific simulation results are as follows.Due to the characteristics of these targets that the scattered wave of echo signal is very low,we bring a method of time reversal technique into our research.The target is irradiated again after the time reversal with the first echo,so as to obtain the stronger echo signal.The following examples verify that energy can focus in time domain and space domain by this technique.Finally,the characteristics of these targets were studied based on time frequency analysis methods and the feature extraction are introduced.In this paper,we discuss the performance of these methods,including STFT,WVD and SPWVD,and use it to do some simulation experiments.And then we extract some effective characteristics of echo signal by the method of PCA,which is a linear algorithm.Some experiments show that this linear algorithm can reflect the characteristics of targets and can reduce the high-dimensional data to lower dimensions,greatly reducing the computation time and improving the computational efficiency.