基于双基ISAR的空间高速目标成像分析

讨论了空间高速运动目标在地基双基地逆合成孔径雷达(Bi-ISAR)系统下的成像算法。首先给出了地基双基ISAR的系统模型及其目标回波信号形式,其次分析了空间目标运动对双基ISAR二维分辨率的影响,在此基础上对回波信号进行分析和处理,通过数学推导得出当目标高速运动时,其回波信号中将产生距离展缩项以及不可忽略的残余视频相位项和脉内走动因子,此后采用构造补偿函数的方法对这些影响成像质量的因素进行补偿,并应用Keystone变换消除成像结果中的越距离单元徙动现象且给出了整个成像处理流程,最后通过对卫星目标的成像仿真验证了文中所分析的距离展宽项和脉内走动因子对目标二维像的成像影响,对补偿前后目标像的比较说明了文中补偿算法的有效性和实用性。

The Imaging Analysis of High Speed Space Targets in Bi-ISAR System

This paper discusses the imaging algorithm of high speed space targets in ground based bistatic Inverse Synthesize Aperture Radar (Bi-ISAR) system. Firstly, the system model and the target echo signal form are given; secondly, the influence of space target moving on two dimension resolution is analyzed. Based on the above, the echo signal is analyzed and disposed, when the targets moves in high speed, it will induce the Residual Video Phase(RVP) and ambulating factor pulse inner ,then the compensation function is constructed to compensate the influence, furthermore, the Keystone transformation is used to eliminate the MTRC and the whole imaging flow is given. Finally, the simulation imaging of satellite target is given to validate that the infection of the RVP and ambulating factor pulse inner can''t be ignored. The comparison between the before and after compensation images shows the effectiveness and practicability of the proposed algorithm.