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逆合成孔径成像激光雷达是一种能实现运动目标超高分辨实时成像的雷达,它在发射激光信号的基础上,运用逆合成孔径原理对目标进行成像。但激光信号具有极高载频、超大带宽和极短波长的特性,传统的距离-多普勒算法不再适用。在对回波信号特征进行分析的基础上,利用重排维格纳分布和Hough变换对光外差探测后的信号进行时频分析以估计目标的运动速度,构造有效的补偿因子,完成了对回波信号的精确运动补偿,并进一步采用Keystone变换完成对目标散射点的越距离单元徙动校正,实现了对目标的高分辨二维成像。仿真实验验证了成像算法的有效性,并通过与微波波段逆合成孔径雷达的比较,证明了逆合成孔径成像激光雷达可实现对运动目标更快速、更高分辨的成像。
Inverse Synthetic Aperture Imaging Lidar is a kind of radar that realizes ultra-high resolution real-time imaging of moving targets. It uses the inverse synthetic aperture principle to image the target based on the laser signal. However, the laser signal has a very high carrier frequency, large bandwidth and very short wavelength characteristics, the traditional distance - Doppler algorithm is no longer applicable. Based on the analysis of the characteristics of the echo signals, the Wigner distribution and the Hough transform are used to time-frequency analysis the signal after the detection of the optical heterodyne, so as to estimate the moving speed of the target and construct effective compensation factors. The accurate motion compensation of the echo signal is also achieved. The Keystone transform is further used to perform the distance cell migration correction of the target scattering point, and the high-resolution two-dimensional imaging of the target is achieved. The simulation results show the effectiveness of the imaging algorithm. Compared with the microwave inverse synthetic aperture radar, it is proved that the inverse synthetic aperture imaging lidar can achieve faster and higher resolution imaging of the moving target.