Based on the framework proposed in Part I, the Part II of this two-part paper investigates two-subarray designs for moving target SAR imaging using planar antenna arrays and the multidimensional Chinese remainder theorem (MD-CRT). In this Part II, we focus on the performance analysis and the detailed two planar subarray designs. In particular, we study a common-scaling two-subarray design, under which the two subarrays share the same scaling factor in the MD-CRT formulation. Under this design, ambiguity resolution can be performed on a common integer frequency vector. As a result, the same unambiguous range as in the general two-subarray framework in Part~I is preserved, while the sufficient conditions for robust recovery become weaker and the corresponding reconstruction error bounds become tighter. Within this common-scaling design, we compare the proposed planar array framework with a conventional separated scheme, in which the motion-induced cross-range shift is recovered by a one-dimensional CRT-based method and the target height is estimated by cross-track interferometric processing. Under the same platform size and minimum antenna spacing constraints, the proposed planar array framework can realize the common-scaling design, whereas the corresponding one-dimensional non-uniform linear array scheme does not admit such a design. With this design, the planar array framework leads to a weaker sufficient condition for robust recovery and thus performs better in moving target imaging. We also compare several planar array designs under fixed platform size and minimum antenna spacing. The analysis shows that recovery performance depends not only on the number of antennas but also on the array geometry. In particular, non-separable planar array geometries can provide better robustness than separable ones when their antenna numbers are comparable.

翻译：基于第一部分提出的框架，本文第二部分研究利用平面天线阵列与多维中国余数定理（MD-CRT）进行运动目标SAR成像的双子阵设计。在第二部分中，我们重点分析性能并详细讨论两种平面子阵设计。具体而言，研究了一种公共缩放双子阵设计，在该设计下两个子阵在MD-CRT公式中共享相同的缩放因子。此设计可对公共整数频率向量进行模糊解算，从而保持与第一部分通用双子阵框架相同的无模糊距离，同时使鲁棒恢复的充分条件更弱，相应的重建误差界限更紧。在该公共缩放设计框架内，我们将所提出的平面阵列方案与传统分离方案进行比较——后者通过一维CRT方法恢复运动引起的跨航向偏移，并利用跨轨干涉处理估计目标高度。在相同平台尺寸与最小天线间距约束下，所提出的平面阵列框架可实现公共缩放设计，而对应的一维非均匀线阵方案无法支撑该设计。采用此设计后，平面阵列框架的鲁棒恢复充分条件更弱，因而在运动目标成像中表现更优。此外，我们还在固定平台尺寸与最小天线间距条件下比较了多种平面阵列设计。分析表明，恢复性能不仅取决于天线数量，还与阵列几何结构相关。特别地，当天线数量相近时，非可分离平面阵列几何结构比可分离结构具有更好的鲁棒性。