基于二维尺度维纳后滤波器的SFCW MIMO雷达成像伪影抑制方法

Artifact Suppression for SFCW MIMO Radar Imaging Based on 2D Scaled Wiener Post-Filter

为了抑制传统后向投影成像方法产生的伪影,提出了一种基于二维尺度维纳后滤波的伪影抑制方法。首先,针对步进频连续波MIMO雷达,将频域BP成像方法建模为一个二维无失真波束形成器;然后,利用带尺度因子的二维维纳后滤波器使波束形成结果的均方误差最小;最后,分析了尺度因子对单目标和多目标成像性能的影响。现有基于相干因子(CF)的伪影抑制方法仅是所提方法具有不同尺度因子时的特例。通过选择适当的尺度因子,该方法可以克服CF方法的一些局限性。仿真结果表明,所提方法在距离向和方位向都能有效地抑制成像过程产生的伪影。

In order to suppress the artifacts in the reconstructed target image obtained by the conventional back projection methods,a 2D scaled Wiener post-filter based method is proposed in this paper.Firstly,for a stepped-frequency continuous-wave(SFCW)radar system,the frequency domain BP(FDBP)imaging method is formulated as a 2D distortion-less beamformer.Then,the 2D Wiener post-filter with a scaling factor is adopted to minimize the mean square error of the beamforming result.At last,the influence of the scaling factor on the imaging performance for both single target and multiple targets is analyzed.Coherence factor(CF)based methods,which have been used for artifact suppression,can be interpreted as the special cases of the proposed method with different scaling factors.By selecting a proper scaling factor,the limitations of CF based methods can be overcome.Simulation results demonstrate that,both in range direction and azimuth direction,the artifacts in the reconstructed target image can be effectively suppressed by the proposed method.