天基ISAR空间目标的去斜回波相参性恢复方法及其基于FPGA的快速实现技术  

A Method for Recovering the Coherence of the Dechirp Received Echo From Space Targets for Space-borne ISAR and Its Rapid Implementation Technology Based on FPGA

作　　者：朱奥 符吉祥 田娇 贺新异 朱元凯 孙光才[1] 邢孟道[1,3] ZHU Ao;FU Jixiang;TIAN Jiao;HE Xinyi;ZHU Yuankai;SUN Guangcai;XING Mengdao(National Key Laboratory of Radar Signal Processing,Xidian University,Xi′an Shaanxi 710071,China;The Unit 93534 of PLA,Beijing 101212,China;Academy of Advanced Interdisciplinary Research,Xidian University,Xi′an Shaanxi 710071,China)

机构地区：[1]西安电子科技大学雷达信号处理全国重点实验室,陕西西安710071 [2]解放军93534部队,北京101212 [3]西安电子科技大学前沿交叉研究院,陕西西安710071

出　　处：《现代雷达》2024年第10期16-25,共10页Modern Radar

基　　金：国家自然科学基金青年基金资助项目(62301389);平湖实验室开放基金资助项目;中央高校基本科研业务费资助项目(20103227364)。

摘　　要：逆合成孔径雷达(ISAR)具备二维高分辨成像能力,可实现对空间目标的高精度探测和监视。相比于地基ISAR,天基ISAR能够对空间目标进行更灵活、更大范围的探测成像,为实现空间态势感知提供有利支撑。去斜接收回波体制可以大幅降低采样率,减轻系统硬件负担,现有ISAR系统通常采用此种方式。然而在观测时间内空间目标相对于星载ISAR的相对斜距变化大,雷达需要不断改变录取波门以保证对空间高速目标的稳定跟踪,这严重破坏了雷达回波的相参性。同时,星载ISAR相对空间目标的复杂运动几何导致运动补偿精度下降。针对空间目标ISAR成像问题,文中提出了一种去斜回波相参性恢复方法,此方法可以逐脉冲处理回波,能有效恢复不同距离波门的回波相参性,并利用估计的参数对回波进行精确的运动补偿。基于此方法,设计了一种基于现场可编程逻辑门阵列的去斜接收相参性恢复快速实现方案。仿真实验验证了所提方法及其现场可编程逻辑门阵列实现方案的有效性。Inverse synthetic aperture radar(ISAR)has two-dimensional high-resolution imaging capability and can achieve high-precision detection and monitoring of space targets.Compared with ground-based ISAR,space-borne ISAR can detect and image space targets in a larger range and is more flexible,which provides favorable support for space situational awareness.Dechirp receiving system can greatly reduce the sampling rate and lighten the hardware burden of the system;hence,this system is usually adopted by spaceborne ISAR.However,during the observation time,the range of the space target relative to the space-borne ISAR varies greatly,so the radar needs to constantly change the wave gate to ensure stable tracking of high-speed targets in space,which seriously undermines the coherence of radar echoes.At the same time,the decrease in the accuracy of motion compensation is brought about by the complex motion geometry of high-speed targets relative to space-borne ISAR.To solve this problem,a method for dechirp receiving coherence recovery of space-borne ISAR for space targets is proposed in this paper,which can effectively recover echo coherence with different range wave gates on a pulse-by-pulse basis,and the estimated parameters are used to accurately compensate for motion.Based on this method,a fast implementation scheme for dechirp receiving coherence recovery based on FPGA was designed.Simulation experiments verify the effectiveness of the proposed method and its FPGA implementation scheme.

关 键 词：ISAR成像 相参性恢复 现场可编程逻辑门阵列 去斜接收 高速目标 

分 类 号：TN957.52[电子电信—信号与信息处理] TN959.74[电子电信—信息与通信工程]