天基合成孔径激光雷达成像参数分析

Parameters analysis of spaceborne synthetic aperture lidar imaging

  • 摘要: 由于空间中没有大气,不存在大气湍流和大气衰减等问题,因此,相对于地基和机载合成孔径激光雷达(SAL),天基SAL有更好的应用前景。为验证中高低轨卫星间SAL成像的可行性,本文中建立了天基SAL成像模型,推导了星对星成像的相干积累时间和脉冲重复频率等参数。利用二体运动轨道外推法,建立了卫星轨道模型。并根据雷达天线波束宽度的限制,计算了激光雷达的收发天线方向图,提出利用目标增益曲线的3 dB波束宽度,获得最大合成孔径时间的方法。最后,通过仿真建立了六种天基SAL应用方式,并分析了不同应用方式下的成像参数,验证了天基SAL成像的可行性。本文的研究为天基SAL成像算法的研究奠定了基础。

     

    Abstract: Since there is no atmosphere in space, problems such as atmospheric turbulence and atmospheric attenuation do not exist. Therefore, spaceborne Synthetic Aperture Lidar (SAL) has a better application prospect than ground-based and airborne SAL. In order to verify the feasibility of airborne SAL imaging, a spaceborne SAL imaging model was established, and the coherent accumulation time and PRF were derived. Then, a satellite orbit model was established by using the extrapolation method of the two-body motion. Next, according to the limitation of the radar antenna beam width, the antenna pattern of the lidar was calculated, and a method to obtain the maximum synthetic aperture time was proposed by using the target gain curve's 3 dB beam width. Finally, six kinds of spaceborne SAL imaging modes were established through simulation, and the imaging parameters under different modes were analyzed, which verified the feasibility of spaceborne SAL imaging. The research of this paper lays a foundation for the research of spaceborne SAL imaging algorithm.

     

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