在电离层的探测与研究中，瞬时多普勒频率可以很好地表明多普勒效应随时间的变化情况，从而反映电离层的变化规律。文中采用相位差分和相位建模两种瞬时频率估计方法，对实际电离层斜向返回探测系统的回波信号进行了仿真，并做出了比较分析，结果显示相位建模方法更能准确反映电离层的变化规律。

In the detection and study of ionosphere, the instantaneous Doppler frequency can indicate the changes that the Doppler effect changes over time, to reflect the change law of ionosphere. Using the two instantaneous frequency estimation methods of the phase difference and phase modeling, the echo signal for actual ionospheric oblique backscattering sounding system is simulated and analyzed. The results show that the phase modeling can more accurately reflect the change law of the ionosphere.