毫米波综合孔径近场成像研究

Study of Millimeter Wave Synthetic Aperture Imaging in Near Field

被动式综合孔径成像的原理是应用干涉原理对亮温度的空域进行采样,并通过傅立叶反变换方法得到视场亮温度分布图像。目前的成像算法都是针对机载或星载对地观测遥感情况,即采用远场条件近似成像算法,但对于隐藏武器探测等反恐情况和实验室试验系统来说,远场成像算法失效,必须寻求实用的近场成像算法。为此,在二维综合孔径成像原理的基础上,从几何校正的角度导出一种新的综合孔径成像近场算法,给出了该算法的计算机仿真结果,并具体分析了该校正后的近场算法的应用条件。通过与点源在远场条件下成像的方法进行了对比,说明该近场算法具有良好的稳定性。

Passive synthetic aperture imaging system is to use an interference principle to sample the brightness temperature in the spatial domain and obtain the images by inverse Fourier transform. The current imaging algorithms are generally applied to airborne and satellite-borne observation, which are the approximate imaging algorithms using the far-field condition. But the algorithms are not satisfied for near flied imaging, so it is necessary to find a near-field imaging algorithm. A new imaging algorithm was deduced for near-field condition from 2D synthetic aperture imaging principle by correcting the geometrical errors, and the computer simulation results of the algorithm were given. The limitations of near field algorithm were also analyzed. The analysis shows that the near field algorithm has a better stability in the imaging of a point source compared to the far-field imaging algorithm.