线性调频SAR回波信号经过二维匹配滤波,所得到二维像具有较高的旁瓣电平,虽然通过幅度加权处理可以降低旁瓣电平,但是主瓣的分辨率会降低。该文针对这一问题,探讨了应用切趾滤波技术来抑制线性调频SAR图像的旁瓣电平的优点,并给出了具体的实现步骤。理论分析和仿真表明,在获得相同的峰值旁瓣电平下,与幅度加权旁瓣技术相比,切趾滤波技术可以保持原SAR图像的分辨率。最后,多目标SAR图像的仿真结果验证了切趾滤波技术的优越性。
It is known that for Linear Frequency Modulation (LFM) Synthetic Aperture Radar (SAR) echo signal, the obtained SAR image by 2-dimensional matched filtering has relatively high sidelobe level. Though such sidelobe can be depressed with amplitude weighting, the resolution of mainlobe will be accordingly reduced. To resolve this problem, in this paper, the apodization filtering technique is discussed and then applied to sidelobe suppression of SAR imaging with the detailed realization procedure presented. The theoretical analysis and simulation results show that in comparison with amplitude weighting, this technique can preserve the resolution of original SAR imaging whilst reducing the sidelobe level. The advantage of this technique has been verified with the simulation results of SAR image in multi-object case.