Patent ID: 9103938
Filing Date: 2015-08-11
Classification: G01C,G01S,G01V,G05D

Abstract:
1. A method for determining a navigational position of a vehicle traversing a terrain, comprising: receiving a first real aperture image of a portion of the terrain being traversed by the vehicle, the real aperture image including acoustic data within a first frequency range obtained from prior imaging of the portion of the terrain; receiving a first position estimate representing a position from which the first real aperture image was obtained; receiving a second position estimate representing a preliminary estimate of a current position of the vehicle; determining a correlation axis connecting the first position estimate and the second position estimate; generating a second real aperture image of the portion of the terrain by insonifying the portion of the terrain with an acoustic signal within a second frequency range directed along the correlation axis, wherein the second frequency range at least partially overlaps with the first frequency range; coherently correlating the second real aperture image with the first real aperture image; and updating the second position estimate based on the coherent correlation.