Patent ID: 6317690
Filing Date: 2001-11-13
Classification: G01C,G01S

Abstract:
A method of performing real-time flight path selection and path planning for general aviation, comprising the following steps:using Digitized Terrain Elevation Data (DTED) to generate a terrain model, said terrain model containing a set of nodes, each of said nodes containing four parameters I,J,K,S, the four parameters I,J,K,S being obtained by mapping each elevation peak point I, J, K of a DTED file into a 3-D locational code of the corresponding Oct-tree, parameters I, J defining the 2-D coordinates of planar location, with elevation K, the parameters I,J,K defining the 3-D coordinates of a space location, and a scaling factor of the elevation being introduced which divides the terrain elevation into bands, parameter K representing scaled elevation, the nodes of said Oct-tree with equal scaled value of elevation occurring in the same quadrant of the corresponding quad-tree being merged, the scaling factor also being non-linear, or beginning with a baseline instead of the mean sea level, parameter S being the coverage area of a node which is added to represent the size of a node, and bit positions of said four parameters I,J,K,S being interleaved to form an integer representation of a node;using this terrain model to provide a navigation space;accessing and retrieving terrain model to generate a terrain map;giving start and goal points on navigation space to determine a ground track of direct flight path on the terrain map;identifying a dangerous zone based on ground track and flight altitude;using said dangerous zone to allocate a set of way-points for avoidance;constructing a visibility graph of navigation space, in which is included a set of collision free path segments;linking start point to goal point by using a flight path searching algorithm; andobtaining the terrain profile of the flight path from the terrain model.