中文摘要：

前视探地雷达的成像处理和地下电磁波的速度估计是前视探地雷达应用中两个重要研究课题。该文利用非平稳滤波矩阵将雷达接收数据经频率域非平稳卷积滤波，实现了目标图像的重建；通过波速扫描和合成孔径成像处理，利用目标图像聚焦的锋利性测度-图像灰度方差估计地下电磁波的速度。对仿真数据和实测数据进行处理，证明了所提方法的有效性。

英文摘要：

The velocity estimation and SAR imaging are the two significant topics for the forward-looking ground penetrating radar （FLGPR）. This paper presents a fast subsurface SAR imaging algorithm with nonstationary filtering matrix for FLGPR. The target image is reconstructed from FLGPR received data after a nonstationary convolution filtering in the Fourier domain. And the velocity of the electromagnetic wave propagating under ground is estimated by using the image gray variance after synthetic aperture imaging with various velocities. The effectiveness of the approach is demonstrated with simulated data and experimental data set.