基于相位线性度的ISAR非平稳目标成像时间选择新算法

该文针对非平稳旋转目标ISAR成像时间选择问题，提出基于相位线性度准则的成像时间选择新算法。首先详细分析了目标非平稳旋转时散射点的相位特性，提出适合目标成像的运动条件；然后基于目标平均距离像提取两个特显点距离单元信号，共轭相乘去除平动相位，相位解缠并曲线拟合得到转动相位，进而评价不同时间段转动相位的线性度，选择线性度大的时刻为成像时间。最后用仿真和实测数据验证了该方法的有效性。

A Novel ISAR Imaging Time Selection Method for Maneuvering Target Based on Phase Linear Degree

In order to select a suitable time interval to reconstruct a well-focused ISAR image for maneuvering target in long recorded data, a novel method based on Phase Linear Degree (PLD) is proposed in this paper. Firstly, the scatterer phase property is deduced in detail and the imaging time condition is given. Secondly, two prominent range cells are selected based on the Average Range Profile (ARP), and the radial phase is removed by the two range cells conjugate multiplication. Then the rotation phase is curve fitting based on the unwrapping phase. Accordingly, the phase linear degree of the rotation phase is evaluated at the different time interval, and the interval with the highest phase linear degree is selected as the imaging time. Finally, the technique effectiveness is tested by simulated and real data.