对地观测卫星固定波束数据传输天线覆盖特性研究

Study on Coverage Characteristic of Data Transmission Antenna of LEO Satellite

从卫星系统设计入手,利用J2轨道模型及星地空间几何关系研究了太阳同步、近极圆轨道、三轴稳定对地观测卫星的星地数传无线链路,得到了在地面站作用范围内均衡接收的波束分布特性。研究结果表明卫星进、出地面站的周向分布是不均匀的,沿卫星飞行方向进、出地面站概率最大,而垂直于卫星速度方向,卫星进、出地面站概率最低;并分析了波导十字缝阵组合天线的覆盖特性。

For earth observation satellites with sun-synchronous, circular orbit and three-axis stabilization attitude, we have studied the wireless link characteristic of data transmission and coverage performance of antenna using J2 orbit model and coordinate transformation. The results show that on the elevation plane the antenna beam should be earth-matched to compensate the space loss and maintain the uniformity of received level of ground station. On the conical surface of the maximum angle, the distribution of actual antenna beam pointing is not uniform. The distribution of beam pointing . when the satellite is entering or leaving the earth station＇s tracking range, is maximum along the flight direction of the satellite, and minimum in the direction perpendicular to the flight direction. So, combination of optimal beam design based on coverage statistics with proper antennas arrangement on-board, better coverage and higher quality of data link could be nchieved.