In scenarios where there is a lack of reliable infrastructures to support car-to-car communications, Unmanned Aerial Vehicles (UAVs) can be deployed as mobile infrastructures. However, the UAVs should be deployed at adequate location and heights to maintain the coverage throughout time as the irregularities of the terrain may have a significant impact on the radio signals sent to distribute information. So, flight altitude and location should be constantly adjusted in order to avoid hilly or mountainous terrains that might hinder the Line-of-Sight (LOS). In this paper, we propose a three-dimensional mobility model to define the movement of the UAV so as to maintain good coverage levels in terms of communications with moving ground vehicles by taking into account the elevation information of the Earth’s surface and the signal power towards the different vehicles. The results showed that our proposed model is able to extend the times with connectivity between the UAV and the cars compared to a simpler two-dimensional model, which never considers the altitude, and a static model, which maintains the same UAV position from the beginning to the end of the experiment.

在缺少可靠的基础设施来支持车对车通信的情况下，可以将无人机（UAV）部署为移动基础设施。但是，由于地形的不规则性可能会对发送来分发信息的无线电信号产生重大影响，因此无人机应部署在适当的位置和高度，以在整个时间内保持覆盖范围。因此，应不断调整飞行高度和位置，以避免可能阻碍视线（LOS）的丘陵或山区地形。在本文中，我们提出了一个三维移动性模型来定义无人机的运动，以便通过考虑地球表面的高程信息和朝向不同车辆的信号功率，在与移动地面车辆的通信方面保持良好的覆盖水平。结果表明，与不考虑海拔高度的简单二维模型和从一开始就保持相同无人机位置的静态模型相比，我们提出的模型能够延长无人机与汽车之间的连接时间到实验结束