基于OpenStreetMap和90 m SRTM的地面站导航 电子地图实现

地面站导航电子地图是操作员用来监控无人驾驶装备的唯一平台,也是进行线路规划和自主决策的重要信息源。现有的导航电子地图一般存在价格昂贵、对高程数据支持不足以及依赖互联网等缺陷。本文提出了一种新的基于OpenStreetMap的地面站导航电子地图实现方法。首先,利用原始OSM数据搭建地图瓦片服务后台;然后将90 m SRTM高程数据处理成地形阴影和地形颜色渐变栅格文件;针对每个栅格文件,在瓦片服务后台的样式配置文件中添加相应图层并定义其渲染格式;最后,在地面站软件中实现地图客户端模块,向瓦片服务后台请求瓦片,并显示在地面站界面上。利用该方法实现的地面站导航电子地图可以提供0~18个缩放级别的中国范围的数据,显示0~13个缩放级别的立体地形地貌,并且无需互联网支持。本文使用该方法实现了某型无人机的地面站导航电子地图模块,并成功应用该无人机仿真系统。

A Realization Method of Navigation Electronic Map for Ground Station based on OpenStreetMap and 90 m SRTM

Navigation electronic map is the only platform for operators to monitor unmanned vehicles. It is also an important information source for route planning as well as auto decision making. A navigation electronic map which covers wide territory and of high precision can provide more details and is an indispensable guarantee for a ground station task. Nowadays, the implementations of navigation electronic maps for unmanned vehicles are mainly based on secondary development on both online and offline map server platforms. These implementations may bring inevitable drawbacks. For one thing, map data and corresponding software such as MapX are very expensive. Even so, the map data always lacks flexibility for personal extensions such as altitude. Besides, the installation and configuration increases much difficulty for the ground station software developers. Finally, online platforms always rely on stable and high-speed Internet network environment, which is not always satisfied. With the development of free and open source geographic data and tools, individuals can easily modify and even construct their own map servers based on their individual needs. In this paper, we provide a new method to implement a navigation electronic map based on a widely crowd sourced map, which is called OpenStreetMap. Firstly, we set up a background tile service using raw OSM data. Then, we render 90 m SRTM data to a bunch of hill-shading and color coding raster files and define the rendering formats and layers in the configure file of the service style for each raster hill-shading and color coding file. Finally, we implement a client module in ground station to request tiles from the background service and present the map in the user interface. The navigation electronic map we implement covers all 0-18 zoom levels of the whole China and it provides 0-13 zoom levels of vivid topographic information and free of Internet limit. Besides, this navigation map we implement can also render other DEM sources and any other raster-format files, such as population, vegetation, precipitation and so on.