针对目标区域不存在图像匹配基准点如对海面目标、草原目标等定位时,基于图像匹配的目标定位方法失效问题,该文提出基于R-D原理的双基前视SAR几何定位方法.首先,在相邻合成孔径中心时刻,利用收发平台与目标的几何关系进行数学建模;再结合地距SAR图像中的目标与场景中心点的关系,解算目标相对接收平台的位置信息;最终,根据双基地前视SAR系统的特点,建立空时频同步误差模型,并结合仿真计算结果给出其对定位精度的影响规律.仿真结果验证了定位方法的有效性及误差模型的正确性.%A geometrical location method based on the R-D principle is proposed. In the case of the location method based on image matching target method will be invalid, when the target area does not have the matching point, such as: sea target, grassland target, etc. First, a geometrical model between the transceiver platform and the target is constructed at the time of center of adjacent synthetic aperture. Then the position information of the target relative of the receiving platform can be solved by combining the relationship between the target in the SAR image and the center point of scene. Finally, according to the characteristic of bistatic forward-looking SAR system, the error models of synchronization errors are built. What is more, through the analysis of the simulation results, the influence of the error on the positioning accuracy is given. Simulation results show the validity of the positioning method and the proposed error models.
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