一种大转角ISAR两维自聚焦平动补偿方法

A Two Dimensional Autofocus Translation Compensation Method for Wide-angle ISAR Imaging

针对ISAR目标在大转角情况下转动和平动分量耦合在一起,难以对平动分量精确补偿的问题,该文提出一种大转角ISAR两维自聚焦平动补偿方法。首先对平动粗补偿,再通过极坐标格式算法(PFA)对转动和平动2维解耦,最后利用自聚焦算法提取误差相位,从中估计剩余平动并补偿。所提方法可以同时校正由平动引起的包络误差和相位误差,且相比于传统的包络对齐级联自聚焦的平动补偿方法精度更高,相比于包络相位联合优化求解方法效率更高。仿真数据和暗室实测数据的实验结果证了所提方法的有效性与实用性。

For non-cooperative ISAR targets, the rotation motion and the translation motion are coupled under wide-angle circumstance, and it is hard to compensate the translation motion precisely. A two dimensional autofocus translation compensation method for wide-angle ISAR imaging is proposed. Firstly, the translation motion is compensated coarsely; then, two dimensional coupling between rotation and translation is decoupled through Polar Format Algorithm （PFA）; finally, the error phase is extracted by autofocus algorithm and then the residual translation is estimated from the error phase. The proposed method can correct the envelope and phase errors simultaneously, and compared with traditional translation compensation methods, range alignment combining with autofocus, the proposed method has a higher precision; compared with the methods of optimization for jointing alignment and phase, the proposed method is more efficient. The experimental results using both simulated data and measured data collected in microwave chamber confirm the validation and practicality of the proposed algorithm.