基于电磁散射模型的海上舰船双基SAR图像仿真

      Bistatic SAR simulation of ships in marine environments via EM scattering models

      • 摘要: 合成孔径雷达(synthetic aperture radar, SAR)在地海环境遥感和目标探测识别中发挥着重要作用。相对于单基SAR,双基SAR能够通过调整发射机和接收机的角度对场景进行多方位观测,因此开展海上舰船目标双基SAR图像仿真可为非合作目标的特征研究和探测识别提供方法和手段,在目标探测识别方面有着重要意义。为此,本文利用基于面元化的简化小斜率近似(facet-based simplified small slope approximation, FBS-SSA)方法与几何光学/物理光学(geometrical optics/physical optics, GO/PO)混合方法,提出了一种基于电磁散射模型的海上舰船目标复合场景双基SAR图像仿真方法,实现了不同双基角下的海上舰船SAR图像仿真,并分析了雷达飞行方向与舰船角度、发射机和接收机相对位置、极化、海况对雷达图像的影响。结果表明,双基角、极化、舰船朝向都会对双基SAR图像产生较大的影响,因此可以通过获取不同双基角度下的复合场景SAR图像特征从而可以更好地开展舰船识别。此外,SAR图像中的阴影特征也可作为舰船识别的辅助手段。

         

        Abstract: Synthetic aperture radar (SAR) plays an important role in remote sensing and target detection and identification of the terrain and marine environments. Compared with a monostatic SAR, a bistatic SAR can observe the scene from different directions by adjusting the position of transmitter and receiver, therefore, the simulation and analyses of bistatic SAR images of ships in marine environments can provide methods and means for feature understanding, detection and recognition of noncooperative targets, which is of great significance in target detection and recognition. For this purpose, based on the facet-based simplified small slope approximation (FBS-SSA) with geometrical optics and physical optics (GO/PO) hybrid method, this paper proposes a simulation method for bistatic SAR of a composite ship-ocean scene, and SAR images of maritime ships are simulated. The effects of ship orientation, coordinates of the transmitter and the receiver, polarization, sea state on radar images are analyzed. The results indicate that the bistatic angles, polarization and ship orientations have effects on SAR images. Therefore, SAR image features from different angles can be obtained by changing the radar angle, which benefits the recognition of ships in marine environments. In addition, shadow features in SAR images can also serve as an auxiliary mean for ship recognition.

         

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