地空信道二径模型及仿真

在对地空通信信道充分研究的基础上,提出“二径模型”可以较好地模拟地空通信链路“通视”条件下的信道。对二径模型的仿真结果表明,主反射波与直射波干涉现象产生的深衰落点附近电平可能会低于系统灵敏度电平,可能会造成系统数据丢失或失去跟踪。三维仿真表明,信道不仅随着距离的变化会出现深衰落,还对某些频率的信号衰落较严重,而另一些频率则衰落较小。这对系统频率的选取有一定的指导作用。

The Model and Simulation of the Two-ray Ground-to-air Channel

Based on the study of the characteristics of the ground-to-air channel,a two-ray reflection model which can fairly simulate the LOS channel of ground-to-air data-link is proposed.The result of simulation indicates that the interposition caused by direct path and ground reflected propagation path can lead a lot of deep fading.The power level near the deep fading point is far below the sensitive level of the system,which can cause the data loss.The three-dimensional simulation indicates that the deep fading occurs not only with the change of the distance,but also with the change of frequency.The three-dimensional simulation result can offer a useful guidance to frequency selection.