合成孔径激光雷达多通道扫描模式及成像方法  

Multi-channel scan mode and imaging method for synthetic aperture ladar

作　　者：李小珍[1] 郭亮[1] 曾晓东[1] 

机构地区：[1]西安电子科技大学物理与光电工程学院,陕西西安710071

出　　处：《光电子．激光》2014年第12期2322-2328,共7页Journal of Optoelectronics·Laser

基　　金：国家自然科学基金(61107006);中央高校基本科研业务费(K5051305005;NSIY171412)资助项目

摘　　要：合成孔径激光雷达(SAL)受激光器件信号调制速率的制约,导致了激光调制带宽和脉冲重复频率(PRF)成为一对矛盾;同时,由于激光信号波长较短,造成波束光斑脚印较小,限制了成像场景的幅宽。基于此,本文提出了一种SAL多通道扫描工作模式下的成像方法。采用多通道体制,以空间采样弥补时间采样的不足,并采用空域滤波方法解决了多普勒模糊的问题;通过控制波束指向,使其周期性的在不同子测绘带之间扫描实现宽测绘带成像。针对扫描模式短孔径对宽场景成像易造成图像模糊的问题,采用谱分析(SPECAN)思想,将图像聚焦在方位频率域。仿真结果验证了本文算法的有效性。Due to the limitation by the velocity of the laser＇s tunable component, the tunable band of ladar contradicts with the pulse repetition frequency （PRF） in synthetic aperture ladar （SAL）. Meanwhile, the swath of SAL is small because of the micro-meter wavelength. In order to solve these contradictions,this paper gives a novel imaging mode of SAL, which combines multi-channel technology and scan mode ima ging system,providing a wide-scene imaging. This system utilizes multiple channels and a few same lenses located in the azimuth direction, which provide spacial information with spacial filtering to remove the ambiguity caused by the low PRF in the Doppler domain. And then, by means of controlling the laser beams which scan in different swaths, a better imaging width can be obtained in spite of accompanying with a reasonable loss of resolution in azimuth. Then,spectral analysis （SPECAN） is adopted to remove the ambiguity caused by the scan mode. As such, the image would focus in the Doppler domain. Finally, simulation with three lenses, e. g. , three channels, can reduce the PRF to be one third of the constraint of the Nyquist theorem. The imaging experiment with numerical data validates the effectiveness of the proposed method.

关 键 词：合成孔径激光雷达(SAL) 宽场景成像 多通道扫描模式 空域滤波 谱分析(SPECAN) 

分 类 号：TN958[电子电信—信号与信息处理]