翻译成英文：根据卫星轨道参数与雷达系统参数，建立准确的星载SAR系统模型是星弹双基SAR成像的基础。除了地球同步卫星外，大部分人造卫星的运行轨道都是以地心为焦点的椭圆轨道。以中轨卫星为例，结合下图，介绍描述卫星轨道的六个重要参数，即轨道六根数。

According to the satellite orbit parameters and radar system parameters, establishing an accurate model of the onboard SAR system is the basis for the imaging of bistatic SAR with satellite and missile. Apart from geostationary satellites, the orbits of most artificial satellites revolve around the center of the earth on an elliptical path. Taking the medium Earth orbit satellite as an example, combining the following figure, six important parameters that describe the satellite orbit, namely the six orbital elements, are introduced.