等离子鞘套下空间高速目标逆合成孔径雷达距离像散焦补偿算法  

ISAR Range Profile Defocusing Compensation Algorithm for Space High Speed Target in Plasma Sheath

作　　者：沈方芳 毛铮 谢曜聪 刘彦明 白博文 陈旭阳 石磊 SHEN Fangfang;MAO Zheng;XIE Yaocong;LIU Yanming;BAI Bowen;CHEN Xuyang;SHI Lei(School of Aerospace Science and Technology,Xidian University,Xi’an 710126,China)

机构地区：[1]西安电子科技大学空间科学与技术学院,西安710126

出　　处：《宇航学报》2023年第5期785-795,共11页Journal of Astronautics

基　　金：国家自然科学基金(61871302);国家自然科学基金(61971330);国家自然科学基金(62171349);陕西省创新能力支撑计划(No.2022td-37)。

摘　　要：针对等离子鞘套包覆空间高速目标ISAR成像时出现距离维散焦问题,开展了等离子鞘套包覆空间高速目标ISAR像距离维散焦机理及补偿算法研究。通过分析等离子鞘套的高速流场分布特性,建立了等离子鞘套包覆空间高速目标的回波模型,通过分析回波信号解线调频处理后的相位解析式,揭示了等离子鞘套流场速度的非均匀分布导致ISAR像距离维散焦的机理。为了实现距离维的散焦抑制,采用分数阶傅里叶变换法对等离子鞘套的耦合速度进行估计,构建了相位补偿因子消除等离子鞘套的影响,最终获得了等离子鞘套包覆下空间高速目标的ISAR距离维可靠成像。最后基于流场数据仿真验证了该算法的有效性。In order to solve the problem of distance dimension defocusing in inverse synthetic aperture radar(ISAR)imaging,the mechanism and compensation algorithm of distance dimension defocusing for ISAR image of high-speed target in space covered by plasma sheath are studied.By analyzing the distribution of plasma-sheath’s high-speed flow field and the mechanism of radar echo coupling velocity,the echo model of plasma-sheath’s enclosing space high-speed target is established.The mechanism of ISAR image distance dimension defocusing due to the non-uniform distribution of plasmasheath’s electron density and flow field velocity is revealed by analyzing the phase analysis formula after the decomposition of the echo signal.In order to suppress the defocusing in the range dimension,the coupling velocity of radar echo is estimated by fractional Fourier transform,and a phase compensation factor is constructed to eliminate the influence of plasma-sheath.Then,obtain the ISAR range dimension reliable imaging of high-speed spatial targets covered by plasmasheath.Finally,the validity of the algorithm is verified by simulation based on the flow field data.

关 键 词：空间高速目标 等离子鞘套 散焦 ISAR成像 相位补偿 

分 类 号：TN957[电子电信—信号与信息处理]