Scattering Center Modelsof Radar Targets And Their Applications

Radar scattering characteristics, scattering center models and their applications has been studied and implemented for some challenging problems in radar engineering, such as radar target feature extaction and target recognition. In this dissertation, we have summarized and further developed the scattering center model theoryby analyzing the aspect dependencies, frequency dependencies of different scattering centers under different radar modes and polarizations, etc. The scattering center model has been applied to miss distance measurement, motion and geometry features extraction, and geometry reconstruction for various radar targets.Scattering center models studied in this dissertation include two parts: the monostatic scattering center model and the bistatic scattering center model. First, we have proposed new classifactions and parameter estimation method for monostatic scattering center model, which establishes the foundation for their application in miss distance estimation and radar target reconstruction. Second, we have proposed an accurate bistatic scattering center model for cone-shaped targets in this dissertation. The model describes the overall attributes of dominant bistatic scattering centers for these targets. It includes not only the sliding scattering centers on the smooth surface and bottom edge, but also the scattering centers induced by creeping waves and traveling waves which are not considered in the previous models. In contrast to the traditional assumption, it is concluded that the scattering centers of creeping waves and traveling waves are important, and can not be ignored particularly under bistatic mode. Finally, bistatic scattering centers induced by creeping waves is particularly investigated, including their characteristics on different shaped cones, and their applications in feature extraction.The developed scattering center models have then been applied to solve several challenging problems. According tothe principle of miss distance estimation, the monostatic scattering center model has been applied to reduce the error induced by the body effect of extended targets. Furthermore, based on the scattering center model, a framework for complex targets geometry reconstruction is proposed by using the time-frequency representations(TFR). Numerical experiments of an unmannedaerial vehicle and a civil aircraft demonstrate the validity of thistechnique.Finally, during the analysis on the bistatic scattering center induced by creeping waves, we have found that the scattering center contains a wealth of information about the geometry and the motions of the target, as well as the relative spacial relationship between the radar and the target. Therefore, by using the information provided by this scattering center, an approach for geometry and motion parameter extraction has been further explored.To assure the reliability of the conclusions, the scattered field data and radar echoes used in this dissertation are all computed by the well-validated full-wave numerical method namely the hybrid finite element-boundary integral-multilevel fast multipole algorithm(FE-BI-MLFMA).