地球同步轨道SAR定轨精度要求分析

Analysis of orbit determination accuracy requirements for geosynchronous SAR

针对地球同步轨道合成孔径雷达(geosynchronous synthetic aperture radar,GEOSAR)的技术特点和应用需求,进行定轨精度要求分析。首先建立GEOSAR定轨误差模型,定性分析定轨误差对斜距及多普勒频率的影响。然后针对全误差公式难以解析求解的问题,提出了一种基于蒙特卡罗法分析定轨精度的方法,并给出GEOSAR典型应用模式下的定轨精度分析流程。最后针对中等倾角GEOSAR给出定量的定轨精度要求。仿真表明,GEOSAR成像聚焦所需的径向位置精度为米级,切向速度精度为10-3 m/s量级,目标定位所需的切向位置精度为10m量级,径向速度精度为10-3 m/s量级,差分干涉所需的径向位置精度为毫米量级,并且下视角越小,约束越高。

The orbit determination accuracy requirements for geosyn-chronous synthetic aperture radar （GEOSAR） are analyzed according to the technical features and application requirements. Firstly, an orbit de- termination error model is developed and the effects on the slant range and Doppler parameters are qualitatively analyzed. Then, considering that it is difficult to solve the whole error formula, a method to analyze orbit deter- mination accuracy is proposed based on the Monte Carlo test method, the analysis processes of the typical appli- cation modes for GEOSAR are also carried out. Finally, focused on the middle-inclined GEOSAR, the orbit deter- mination accuracy requirements are given. Simulation results verify that the accuracy of the radial position should be at meter-level and the tangential velocity at 10-2 m/s level for GEOSAR imaging, the tangential position should be at 10 meter-level and the radial velocity at 10-3 m/s level for GEOSAR target positioning, and the radial position should be at millimeter level for GEOSAR differential interferometry, and the smaller down angle is, the higher constrains are.