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针对弹载合成孔径雷达(SAR)回波信号的多普勒参数随斜距变化大及传统脉冲压缩成像算法分辨率低的问题,本文提出了一种基于分数阶傅里叶变换(FrFT)的弹载SAR成像算法.首先建立弹载SAR末制导阶段回波信号模型,然后通过局部最优处理来测量回波信号的调频率,并以此计算FrFT的最优阶次,在最优阶次下分别对回波信号进行距离向和方位向的FrFT,从而得到成像区域的SAR图像,最后分别采用传统脉冲压缩成像算法与本文基于FrFT的成像算法进行仿真和实测对比实验.实验结果表明,该算法能够对目标区域精确成像;由于在成像处理过程中,对每个距离向和方位向的回波信号进行独立的局部最优处理,因此该算法更适应于弹载SAR的非线性飞行轨迹,大大提高了弹载SAR的成像性能.该研究成果在目标探测与识别,精确制导等领域中具有重要的应用价值.
Aiming at the problem that the Doppler parameters of the echo signal of missile synthetic aperture radar (SAR) vary greatly with the slope distance and the resolution of the traditional pulse compression imaging algorithm is low, this paper presents a novel method based on Fractional Fourier Transform The algorithm of missile-borne SAR imaging firstly sets up the echo signal model of the end-of-missile guided SAR and then measures the tuning frequency of the echo signal by the local optimum processing to calculate the optimal order of FrFT. Respectively, the distance and azimuth FrFT of the echo signals are respectively obtained to obtain the SAR images in the imaging area, and finally the traditional pulse compression imaging algorithm and the FrFT-based imaging algorithm are respectively used in the simulation and the experimental comparison experiments. The experimental results show that the The algorithm can accurately image the target region. Because of the independent local optimal processing of each range and azimuth echo signals in the imaging process, the algorithm is more suitable for the non-linear flight path of the missile-borne SAR, Greatly improves the imaging performance of the missile-borne SAR.The research results have important application value in the fields of target detection and recognition and precise guidance.