基于时频分析的电离层多模污染抑制研究

研究高分辨线性时频分析方法和联合时频分析方法，利用这两种方法对高频电离层返回散射探测的多个传播模式实测数据，对污染抑制效果进行分析.结果显示，这两种基于时频分析的方法针对多模和相位污染同时存在的复杂情况，与其他常规方法相比均使杂波谱得到了较好的锐化，目标信号在二维时频域较清楚地显出.因此可以证明，上述两种方法具有很高的应用价值，对天波超视距雷达海上低速目标检测具有重要意义. 

Study on Ionospheric Multi-mode Propagation Pollution Suppression Based on Time-frequency Analysis

The high resolution linear time-frequency analysis method and the combined time-frequency analysis method are the theoretically analyzed and verified by simulation in this paper. And these two methods are applied to high frequency ionospheric backscattering detection data that have ionospheric multi-mode propagation state. The effect of ionospheric pollution suppression is analyzed. Results show that these two methods have better effect in the case of ionospheric multi-mode propagation state and phase pollution exist at the same time. These two methods can make spectrum more sharpening than other conventional methods. The ship target is clearly revealed in time-frequency domain. Thus it is proved that these two methods have very high application value. For sky-wave over-the-horizon radar detection of low speed targets like ships, these two methods are of great significance.