地空低仰角通信的分析

Analysis of ground to air low elevation communication

由于空域管理限制,民用无人机升空高度有限,民用地空通信多数属于低仰角通信,多径与衰落很严重。对传播信道引起的衰落与频率、距离、天线高度等众多因素的相互关系进行研究,是通信系统设计及参数选取的基础性工作。首先进行仿真研究,找到距离、天线高度、频率与衰落之间的数值关系,可以作为后期实际测试研究的重要参考;为保证传输质量,提出双频分集传输、地面设备在不同高度部署两部天线进行分集接收的基本系统配置建议,以降低机载端发射功率,适应无人机平台载荷能力的限制。

Due to the limitation of airspace management,the altitude of civil UAV is limited,and most of civil ground to air communication belongs to low elevation communication,with serious multipath and fading.To study the relationship between fading caused by propagation channel and many factors such as frequency,distance and antenna height is the basic work of communication system design and parameter selection.Firstly,simulation research is carried out to find the numerical relationship between distance,antenna height,frequency and fading,which can be used an important reference for later actual test research;in order to ensure the transmission quality,the basic system configuration suggestions of dual frequency diversity transmission and ground equipment deploying two antennas at different height for diversity reception are proposed,so as to reduce the airborne transmission power and adapt to the UAV platform load capacity limitation.