由于双基地雷达中两极区双基地角的时变特性, 传统ISAR成像法无法获取高分辨的目标像.分析了两极区双基地角的时变性及对距离包络和方位的影响, 就两极区目标运动模型中目标方位高次项提出了Radon-TCDS-Relax超分辨成像算法, 对每个距离单元进行调频率和调频率变化率搜索并补偿其所对应的方位高次相位误差, 用Radon-TCDS-Relax提取散射点实现TCD-RID 成像.仿真实验与分析验证了本文方法的有效性.

For the time-variant property of bistatic angles in Receiver Centered Region Area in bistatic radar system, it′s difficult to obtain high resolution ISAR image of target in by using the conventional imaging methods.The signal model for bistatic ISAR was presented, then the time-variant property of the bistatic angles and its influence on range envelope and azimuth was analyzed.A Radon-TCDS-Relax super-resolution imaging method was brought up for eliminate the effect from high-order azimuth terms of target motion model in receiver centered areas.The chirp rate and its changing rate corresponding to high-order phase terms in cross range was estimated by the proposed method.Scatterers extracting and imaging were achieved by Radon-TCDS-RELAX and TCD-RID respectively.Accuracy analysis and the experimental results with real data both demonstrate the effectiveness of the proposed method.