星载SAR天线高稳定度指标分配方法研究

Assignment method for the high stability index of a spaceborne SAR antenna

为研究大型星载SAR天线的高稳定度指标分配问题,根据天线在轨运行的实际环境设计了三种仿真工况,运用ADAMS对SAR卫星天线进行多体动力学分析,并提出运用概率法对指向精度进行合理分配。结果表明:在具有相同有效载荷且距离天线位置相对较近的部位施加扰动对SAR天线的指向精度影响较大,且影响程度由大到小依次为:隔振器扰动、CMG调姿扰动、SADA扰动。三个视角对天线指向精度的影响程度由大到小依次为:俯仰角、方向角、距离角。提高隔振器的隔振性能,减少有效载荷的扰动对卫星天线指向精度的影响,在多种成像模式切换的过程中加强对俯仰角的控制,可以有效地提高SAR卫星天线的成像质量,并为卫星总体选择合适型号的调姿机构提供帮助。

Three kinds of simulation conditions were designed to study the high stability index assignment of a spaceborne SAR antenna according to the practical environment of the antenna on orbit.By analyzing the SAR antenna with the multi-body dynamics software ADAMS,the pointing accuracy was rationally allocated by the probabilistic method.The results show that the influence of disturbances on the pointing accuracy of the SAR antenna is greater if the disturbing load is acting on the area closer to the antenna.And the order of their influence degree is as follows:vibration isolator disturbance,CMG disturbance and SADA disturbance.The influence degree of the three angles on the pointing accuracy of the antenna is in the following order:pitch angle,direction angle,and distance angle.Improve the performance of the vibration isolator,reduce the effect of the payload disturbance on the pointing accuracy and improve the pitch angle control in the process of switching between various imaging modes,the SAR satellite antenna will be able to improve the SAR satellite image quality and help the satellite overall to select the adjustable posture institution.