逆合成孔径成像激光雷达在空间小目标成像中的应用

Applications of Inverse Synthetic Aperture Imaging Laser Radar to Image Reconstruction for Small Space Target

针对空间小目标实现毫米级的二维图像重建,构建了基于逆合成孔径激光雷达成像系统。通过大带宽线性调频技术获得高分辨率距离向数据信息,通过"一步一停"模式多点位数据采集获得高分辨率方位向数据信息,再将两者进行图像融合得到二维合成图像。给出了空间小目标的运动特性,在分析了自旋分量与平动分量的基础上,论证了转台模型模拟空间小目标的可行性。试验针对毫米级细铝条进行二维图像重建。试验结果显示:重建图像在边缘位置上重叠较多,而在中心位置上重构密度较弱,但仍可清晰地识别出小目标,满足设计要求。

In order to achieve millimeter-level two-dimensional image reconstruction of small space target,image reconstruction system was designed based on inverse synthetic aperture imaging lidar( ISAIL). The high-resolution distance direction data were obtained by large bandwidth linear frequency modulation technology. The high-resolution azimuth direction data were obtained by a step stop mode and multi-bit data acquisition. The two-dimensional composite image was obtained by the fusion of two group data. Motion features for small space target were given. Based on the analysis of the spin component and the translational component,turntable model was feasible to detect small space target. In the experiments,two-dimensional image reconstruction was implemented for millimeter thin aluminum. Experimental results show that overlapping of image is more on the edge. Reconstruction of density is weak in the center,but the small target can clearly be identified,which satisfies the design requirements.