基于短波信道模型的天波雷达回波模拟方法

Methods of Simulating SOTHR Echo Based on HF Channel Model

针对目前采用传统的视距雷达回波模拟方法模拟天波雷达的回波时,不能准确描述电波通过电离层传播后在信号的相位上叠加的准随机扰动的问题,提出了一种采用发展较为成熟的短波宽带信道模型———ITS模型来模拟雷达回波的方法。该方法首先根据信道实测参数结合雷达回波的要求,将功率延迟函数近似为一定值,确定相位函数对应一确定性函数,随机调制函数则采用滤波法产生的一组复随机序列代替;然后将电波在空中传播的过程拆分为两个阶段,并分别运用ITS模型计算相应的传播信号,从而最终得到天波雷达的回波信号。仿真表明:采用该方法模拟的回波信号符合要求,并能够较准确地模拟由电离层影响导致的天波雷达回波信号的确定性相移和准随机相位扰动。

The traditional methods of simulating sky-wave over the horizon radar＇s（SOTHR） echo can not accurately describe the quasi-random perturbation that superimposed on the signal phase after the wave propagating through the ionosphere.Based on the ITS wideband high frequency（WBHF） channel model,an echo simulation of SOTHR was presented in this paper.According to the measured channel parameters combining with radar echo request,the power delay function was approximated for a certain value,the phase function was corresponded to a deterministic function and the random modulation function was replaced by a complex random sequence generated by filter.Then the process of wave propagation was split into two stages which were both calculated with ITS model to obtain the radar echo signal ultimately.Simulation results showed that echo signal simulated by the method was in accordance with the requirements,and could simulate precisely the deterministic phase shift and quasi-random phase perturbation of the sky-wave radar echo which caused by the ionosphere influences.