自旋式飞行器三维SAR成像及测高新模型

 自旋式飞行器由于运动轨迹复杂,不仅不能精确测量飞行高度,而且从未被用做SAR成像平台。通过研究自旋式飞行器的三维SAR成像新模型,将测高与三维SAR成像相结合,提出了一种基于三维SAR成像的测高新模型。首先分析了自旋式飞行器天线相位中心运动轨迹的特点,将具有三维空间分布的半螺旋线天线运动轨迹等效为面阵天线;然后基于等效面阵,利用模糊函数理论,推导了相应的三维成像模型,从理论上证明了模型的成像可行性并分析其成像性能;最后在成像模型基础上,提出基于三维SAR成像的自旋式飞行器测高新模型,并从成像角度分析影响测高精度的因素。针对等效面阵非均匀分布的特点,采用后向投影(BP)算法仿真验证自旋式飞行器模型下三维成像的可行性和测高模型的有效性。

A novel model of spin aircraft 3D SAR imaging and height measurement

Due to the complexity of movement, spin aircraft is never regarded as a general platform for SAR imaging and its accurately measured height is not easy to obtain. In this paper, through studying a new 3D SAR imaging model of spin aircraft, the height measurement is combined with 3D SAR imaging. A height measurement model based on 3D SAR imaging is proposed. Firstly, through the analysis of antenna phase center''s trajectory, the half spiral trajectory is equal to the antenna array. Then, based on the equivalent plane array and the fuzzy function theory, a novel spin aircraft 3D SAR imaging model is put forward, the feasibility of 3D imaging is theoretically proved and imaging performance of the model is analyzed. Based on this imaging model, this paper proposes a height measurement model based on 3D SAR imaging and the factors that affect measuring precision are analyzed. According to the characteristics of the equivalent plane array non-uniform distribution, back projection (BP) algorithm is used to verify the feasibility of the 3D imaging model under the spin aircraft and the effectiveness of the height measurement model.