| The invention of radar is an important turning point in modern military. Radar can not only detect the target, but also get the image of ground and objects. Radar faces with new challenges in target detection as the invention of stealth technology. By using the technology of shape stealth and materials stealth, stealth targets are difficult to detect by traditional radars. The multiband electromagnetic scattering characteristic and imaging characteristic of stealth aircraft which not consider the coating materials are researched in the first part. In addition, synthetic aperture radar images’ appearance has opened up a new branch in target identification, and the related techniques of automatic image interpretation become the focus of current research. The removal of interference fringes in synthetic aperture radar image and the extraction of strong scatters are researched in the second part. The main contents are as follows:(1) To do the analysis of multiband electromagnetic scattering characteristic and imaging characteristic, the F-22 stealth aircraft is used as an example. First, the NURBS surface model of stealth aircraft is built, and the surface element is meshed. Then, the full-wave electromagnetic simulation software and high frequency electromagnetic simulation software are used to calculate the radar cross section. To provide a reference for multiband anti-stealth technology in military, the detailed analysis of the radar cross section with frequency changes is done.(2) The radar images of stealth aircraft which are get from different horizontal angles and pitching angles are used to analysis imaging characteristics in contrast to the radar images of non-stealth aircraft. This job provide a reference for the anti-stealth technology in military.(3) The removal of interference fringes in synthetic aperture radar image is researched based on the simulation synthetic aperture radar images. According to the spectral characteristics of the interference fringes, the "zero phase shift filter" is designed, and the associated experiments of the removal of interference fringes are done.(4) According to the characteristics of synthetic aperture radar imaging, the image segmentation is completed by the watershed algorithm, and the strong scatters are extracted. The images are reconstructed by Gaussian Model and are compared with the original images. The experimental results demonstrate the effectiveness of the extraction algorithm of strong scatters based on Gaussian model. |
PDF Full Text Request