基于自适应最优核时频分布理论的ISAR成像方法

ISAR Imaging Based on Adaptive Optimal Kernel Time-Frequency Representation

由于运动的复杂性,传统的成像方法已无法满足机动目标成像的要求。在分析机动目标复杂运动引起目标回波多普勒相位非线性变化的基础上,提出了一种基于自适应最优核时频分布(AOK TFR)理论的ISAR成像方法。通过计算回波数据不同距离单元的AOK TFR,得到不同时刻目标的瞬态ISAR像,且不受交叉项的影响;通过估计距离单元的瞬时多普勒频率并依此对成像时间段进行选择。仿真数据结果验证了该方法的有效性。

Because of target＇s complicated movement, conventional ISAR imaging algorithm can not meet the demands of maneuvering target imaging. On the basis of analyzing the echo＇ s non-linear Doppler shifts caused by maneuvering target movements, a new ISAR imaging method based on AOK TFR is proposed. The instantaneous target images can be obtained by calculating the AOK TFR of different range bins. Compared with the classical time frequency distribution, the AOK TRF has no cross item interference from multicomponent signals. Meanwhile, the instantaneous Doppler frequencies of echoes in range bins are estimated. According to the estimated Doppler frequencies, imaging time can be selected. The simulationd results demonstrate the validity of the proposed method.