低轨卫星多普勒频移特性的快速计算

地面站利用低轨卫星进行通信时,地面接收站接收信号存在明显的多普勒频移现象。为描述多普勒频移特性,首先分析卫星轨道偏心率对多普勒特性曲线的影响,分析表明：轨道偏心率越大,地面站接收信号多普勒变化率越大。其次,推导了卫星多普勒频移的计算表达式,并讨论了低轨卫星多普勒频移特性曲线的快速计算。仿真计算结果表明,该算法可以很好地描述任意低轨道卫星多普勒频移特性,并明显缩短了精确算法的计算时间,对于10 000km轨道高度卫星,算法置信度可达99%以上。

Fast Doppler Estimation for LEO Satellites

Significant Doppler shift is observed by ground-based terminals when they communicate through LEO （Low Earth Orbit） satellites and it is essential to characterize Doppler shift in order to get reliable satellite communi-cation links. As shown by analysis of the effects of orbit eccentricity on Doppler-time curves measured by a user on the surface of the earth, Doppler rate increases as the orbit eccentricity of the satellite increases. Furthermore, the Doppler shift expression of a ground-based terminal is derived and avenues that diminish time consumption in Doppler characterization computation are discussed. The approach is validated by numerical simulation. Accurate Doppler-time curves are nicely fitted and the accuracy of the algorithm is higher than 99 % for satellites with an orbit altitude of 10 000 km.