The Research On Equivalent Parameters Inversion Technique Of Electromagnetic Model In The Typical Terrains

The radar system of Microwave remote sensing has been widely applied to the environmental monitoring of the surface and the targets detection and recognition. Nowadays, there has been a large number of terrain scattering models on the rules of electromagnetic wave scattering behavior of the surface, which include two aspects of the forward and inverse scattering problems. The forward scattering is that when the reasonable roughness and dielectric input into the electromagnetic scattering model, it can generate radar echo of the terrain. While the inverse scattering is to inverse roughness and dielectric parameters combining the measured backscattering coefficient and the scattering models. These two aspects are relatively independent because of the different research motivations. At the same time, in order to make the scattering model be used in engineering, it is crucial to ensure the accuracy of the input parameters apart from the scattering models. Therefore, researching on the effective mapping from the natural language to the algorithm language and getting the equivalent parameters’ models are the important premise about the practical application of random surface scattering models.In this thesis, first, several typical terrains in the nature are introduced, and their dielectric constant models are also set up. Then two key parameters about geometric features and the initial range of every terrain are introduced. And then several electromagnetic modeling methods of the random rough surfaces are presented, focusing on the integral equation model and its verification, to know the influence of geometric parameters. Then through the backscattering actual data and the electromagnetic models about the terrains, equivalent parameters ranges are inversed by Genetic Algorithm. In order to achieve the purpose of getting parameters’ boundary, two new methods are proposed based on the traditional Genetic Algorithm. The one is reversed mutation to get multi-solutions, which researches more suboptimal solution after having gotten the optimal solution. The other one is the criterion to stop the iteration, which is by judging the repetitive rate of the individuals, and it can also ensure the integrity of the solution set. Finally, equivalent parameter models are established using the results by inversion, then verified and the error analysis. The result is good, because the electromagnetic model calculation results whose parameters are calculated by equivalent parameter models match the actual terrains well.Once the method is mature, it will enrich the rear-end database of the simulation software and provide the effective input parameters for the terrain simulation models, which practice the application of the forward scattering. Moreover, the backscattering coefficient calculated by the geometric parameters using the equivalent parameters range models can be the measured data of the bistatic, which provides the premise for the bistatic electromagnetic models.