Grid-based coding of terrain maps for localization

Abstract

Encoding terrain maps is provided. The method comprises receiving a digital elevation model (DEM) of a terrain and encoding the DEM into grid cells parameterized by spatial scale, orientation, and 2D offset. Grid cells with shared scale and orientation are aggregated into grid modules. Locations from the DEM that correspond to a given elevation produce a contour line of locations that fall within the given elevation. 2D phase codes are calculated for each grid module to produce a phase candidate dictionary, wherein a subset of phase codes comprises phase candidates corresponding to locations from the contour line. When sensor data is received along a trajectory over the terrain, the phase candidate dictionary is queried. Phase candidates are corrected for relative displacement from a reference point and summed to produce a coincidence map over the DEM that identifies a current location estimate over the terrain.