针对多普勒中心频率估计值对合成孔径雷达(SAR)成像信号能量聚焦性能的影响,文中首先确立距离向分数阶傅里叶变换(FrFT)域能量聚焦轴,然后推导分析距离向分数阶傅里叶变换域能量聚焦轴与多普勒中心频率的关系式,接着构建距离向FrFT域成像算法(RFrFT-RD),最后利用星载SAR实测数据进行地物目标成像。实验结果表明,当多普勒中心频率估计值误差由0逐步增大到5%时,所提RFrFT-RD算法具有较好的成像性能稳定性。与传统的距离多普勒(RD)算法相比,所提算法距离向分辨率绝对值平均提高约7.69m,而距离向峰值旁瓣比(PSLR)平均降低约1.88dB,距离向积分旁瓣比(ISLR)平均降低约2.89dB。

Aiming at the influence of Doppler central frequency estimation on the energy focusing performance of synthetic aperture radar (SAR) imaging signals, in this paper firstly the energy focusing axis in the range fractional Fourier transform (FrFT) domain is constructed, then the relational formula between the energy focusing axis in the range FrFT domain and the Doppler central frequency is derived, the range FrFT domain imaging algorithm (RFrFT-RD) is constructed, and finally the measured data of spaceborne SAR is used to image ground objects. The experimental results show that RFrFT-RD algorithm has good stability of imaging performance when the error of Doppler center frequency estimation gradually increases from 0 to 5%. Compared with the traditional range Doppler (RD) algorithm, the absolute value of the range resolution of proposed algorithm is increased by about 7.69 m onaverage, while the range peak sidelobe ratio (PSLR) is reduced by about 1.88dB on average, and the range integral sidelobe ratio (ISLR) is reduced by about 2.89dB on average.

TN957. 52

全国高等学校计算机教育研究会课题资助项目(CERACU2022R27);“十四五”江苏省重点学科“网络空间安全”建设项目;江苏省教育科学规划课题 资助项目(D/2020/01/22);江苏警官学院高层次引进人才科研项目(JSPI19GKZL405)