Research on ISAR Imagine of High Frequency Ground Wave Radar in Large Sea Scene

High frequency ground wave radar (HF-GWR) is considered as a new and effective technical tool for marine environmental monitoring because of its advantages of beyond visual range, large range and low cost, meanwhile, ISAR (Inverse synthetic Aperture radar) imaging technology has great application value in the strategy of maritime power. In this paper, PM sea spectrum and linear filtering method were used to simulate the wind driven sea surface, and combined with the digital elevation model (DEM), a large sea scene where the island target and the sea surface are combined is successfully constructed. Then, high-frequency numerical electromagnetic calculation method was used to obtain the broadband and large angle echo data of the sea scene. Finally, the echo data are processed by Simpson integral, and the 2D ISAR image of large sea scene with high/low extreme sea conditions at low sweep angle and high frequency band (working conditions of HF-GWR) is obtained successfully. The imaging results show that the contour of island targets and strong scattering points such as ridge lines can be clearly displayed under extreme sea conditions, which has a reference significance for the application of distributed/mobile HF-GWR in 2D ISAR imaging engineering of large sea scene.