卫星通信中,星地双方高速移动及快速角度变化等因素,将造成较大多普勒频移及频谱扩展等现象,恶化星地通信性能.在Walker星座计算多普勒频移算法的基础上,提出了改进的中椭圆轨道卫星多普勒频移的快速简化计算方法.相对于传统卫星在宇宙空间的三维坐标复杂公式计算方法,所提方法通过长半轴、偏心率等参数直接计算卫星半径,较大降低了计算复杂度.最后,仿真对比和分析高椭圆轨道通信卫星的多普勒频移曲线,较好地解释了中椭圆轨道多普勒频移特性.同时,仿真星地在相对运动情况下的多普勒频移特性,验证了其有效性,以便于实际卫星通信场合快速估计多普勒频移而有效辅助信号接收.%In satellite communications, the high-speed movement, the rapid angle change and some other factors of between the satellites and the ground stations would usually, cause fairly large Doppler frequency shifting, spectrum spreading, and other phenomena, thus deteriorating the satellite-ground communication performance. Based on the Doppler frequency shift algorithm under the Walker constellation a modified calculation method of the Doppler shift in the medium elliptical orbit satellite is proposed. Compared with traditional formula methods needing to know three-dimensional coordinates of the satellites in space, the computational complexity is greatly reduced through directly calculating the radius of the satellite by the semi-major axis of ellipse, eccentricity and other parameters. Finally, simulation comparison and analysis of the Doppler frequency shift curves in high elliptical orbit communication satellites fairly interprets the characteristics of medium elliptical orbit Doppler frequency shift. In addition, simulation on the characteristics of medium elliptical orbit Doppler frequency shift for the relative motion of between satellite and ground station indicates the effectiveness of this algorithm. All these could facilitate the rapid estimation of Doppler frequency shift and effectively support the signal reception in actual satellite communications.
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