MEO星弹双基SAR多普勒特性及分辨率分析

中地球轨道SAR具有波束范围覆盖广、重访时间短等特点，将其作为发射平台，弹载SAR作为接收平台，可以大范围面、高机动性地对重点区域高精度成像。根据空间系统模型建立MEO星弹双基SAR等效模型，对收发平台斜距模型进行描述，将其等效为多项式模型，并分析了孔径时间内的斜距误差，验证模型有效性；根据平台特性重新分析多普勒特性，得到多普勒中心频率和多普勒调频率的二维空变特性；运用梯度法计算距离分辨率、方位分辨率，并分析其随成像区域的变化情况。仿真实验表明，成像区域内的分辨率受俯冲速度的影响是不均匀的，应改变斜视角或改变双基构型，使关注的目标处在受速度影响较小的区域。

Doppler Characteristics and Resolution Analysis of MEO Space-Missile Borne Bistatic SAR

Being characterized by wide beam coverage and short revisit time, taking the MEO as a transmitting platform, and the missile borne Bistatic SAR as a receiver platform, the image can be made in the key areas with a wide range and high mobility. In this paper, the equivalent model of MEO space\|missile borne BiSAR is established based on the space system model, and the slant range model of the transceiver platform is described, which is equivalent to a polynomial model. The slant range error in the aperture time is analyzed to verify the validity of the model. According to the characteristics of the platform, the Doppler characteristics are re\|analyzed, and the two\|dimensional space variation characteristics of the Doppler center frequency and Doppler modulation frequency are obtained. The gradient method is used to calculate the range resolution and azimuth resolution, and analyze their changes with the imaging area. The simulation experiment shows that the resolution in the imaging area is not uniformly affected by the subduction velocity, and the oblique angle of view or the double base configuration should be changed so that the target concerned is located in the area less affected by the velocity.