具有三维转动目标的ISAR成像新方法

New method for ISAR imaging with three dimensional rotation targets

传统的逆合成孔径雷达(inversesyntheticapertureradar,ISAR)距离 多普勒成像算法基于目标平稳飞行假设。当目标作机动飞行时,转速和转轴经常是时变的,采用传统方法成像会使图像模糊,甚至无法辨识。为此需要分距离单元进行时频分析,得到距离 瞬时多普勒图像。采用重排后的平滑伪Wigner Ville分布(smoothedpseudoWigner Villedistribution,SPWVD),既克服了WVD交叉项严重,不能正确成像的缺点,又克服了SPWVD降低时频集聚性,不能准确定位的缺点。仿真结果表明,该方法对机动目标能得到高质量的雷达图像。

When the target moves irregularly, the Doppler of each scatter and the imaging projection plane to a maneuvering target may change with time. The traditional RD algorithm is no longer suitable to the maneuvering target. In this case, time-frequency analysis must be taken for every range cell to obtain range-instantaneous Doppler imaging. The proposed reassigned smoothed pseudo Wigner-Ville distribution (RSPWVD) is much better than Wigner-Ville distribution (WVD) and smoothed pseudo Wigner-Ville distribution (SPWVD), which not only reduces the interference terms but also keeps good time-frequency concentration. Simulation data prove that RSPWVD can get good radar imaging for maneuvering targets.