Abstract: The purpose of this article is to enhance the sensing capability of ground navigation officers through three-dimensional virtual terrains generated by real time remote information of aircraft status, so as to enable them to guide pilots in dealing with complex flight conditions appropriately. To create a virtual terrain, firstly a coarse sample mesh is generated by persistent grid mapping (PGM) in the algorithm. Then a continuous level-of-detail (LOD) factor is assigned to each triangle respectively based on its distance to the view point in the geometry shader. Afterwards, the factor is used to choose and blend proper levels of satellite images stored in a two-dimensional texture array in the pixel shader. Because of its continuity, the transition between different levels of textures can be smooth. Thus, the scene looks more natural and realistic. Finally, considering the capability limitation of the memory on a video card, a dynamic loading strategy is employed to manage the textures. Because the simulation is geared toward high utilization of the graphic processing unit (GPU), large-scale terrains of multiresolutions can be generated interactively according to the demands of both real-time and reality. The algorithm in the presented form is used operationally within a flight monitoring system to support the flight test of the Advanced Regional Jet at flight laboratory.

Key words: flight monitoring, GPU, level-of-detail, multiresolution terrain, real time systems