合成孔径激光雷达多通道TOPS模式及频谱恢复方法

Multi-channel TOPS Imaging Mode and Spectrum Reconstruction Method for Synthetic Aperture Ladar

针对多通道循序扫描地形观测模式中单个通道的回波数据在方位向存在模糊,采用传统空域波束形成技术及方位预滤波方法均无法恢复信号频谱的问题,在分析产生模糊原因的基础上,提出了一种基于谱压缩的空域波束形成方法.该方法首先对信号进行反旋处理,压缩信号的频谱宽度;然后对多通道数据进行空域波束形成,获得无模糊的频谱;最后对信号反旋处理引入的相位项进行补偿,得到原始信号的二维频谱.点目标及场景仿真实验数据处理结果均验证了该算法的有效性.

Synthetic aperture ladar can work with low pulse repetition frequency and obtain wide scene with muti-channel in terrain observation by progressive scans mode.However,the frequency spectrum in azimuth of the raw data in each channel is ambiguous,which ambiguity can not be removed by conventional spactial beamforming.To solve this problem,a novel method of spactial beamforming based on spectral compressing was proposed.Firstly,a transformation in azimuth was introduced with deramp technology.Then,spactial beamforming was used to remove the ambiguity.Thirdly,aphase factor was used to compensate the phase error induced by the deramp.Finally,a conventional imaging algorithm can be used to abtain images from unambiguous data.The imaging experiment with numerical data validates the feasibility and effectiveness of the proposed method.