机载情报侦察数据链中的空地链路建模与仿真

针对机载情报侦察链中空地通信链路的特点,建立了统一的信道模型。模型包括大尺度衰落模型和基于三径信道模型的小尺度衰落模型。在给出了信道衰落模型的具体仿真方法后,分析了飞机飞行距离、工作频率及径向飞行速度等参数对信道特性产生的影响,为进行链路预算和解决多径干扰提供理论上的依据和参考。结果表明：不管信息传输速率多大,由于多径的影响在飞机飞行过程中频率选择性衰落都是不可避免的,但信息传输速率越高,衰落越严重;多普勒频移并不直接影响信道特性,但多径信道下的多普勒频移通过引起多普勒扩展而使信道具有了时变性。

Air-ground channel model for airborne intelligence, surveillance and reconnaissance data link

The characteristic of air-ground link in airborne ISR（Intelligence,Surveillance and Reconnaissance） data link is analyzed,and a unified channel model is built.The channel model includes large-scale fading model and small-scale fading model based on the three-path fading channel model.The simulation method of the fading channel model is designed.The characteristics of the channel are discussed with different parameters： flight distance,frequency and radial velocity.The analysis results can provide a theoretical basis and reference for link budget and solving the multi-path interference.The simulation results show that due to the impact of multipath,no matter how much information transfer rate is,selective fading is inevitable on the plane;Doppler frequency shift does not affect the channel characteristics directly,but with the effect of multipath,it causes expansion of Doppler frequency and makes the channel time-varying.