Patent ID: 8307705
Filing Date: 2012-11-13
Classification: G01C

Abstract:
1. A method for laser hydrography comprising at least one laser beam emitted from a known location in a known direction onto the surface of a body of water and through the water onto the bottom of the body of water and measurement points of the water surface and the water bottom in a coordinate system are determined from transit-time measurements of reflections of the laser beam at the water surface and water bottom, wherein a local inclination of the water surface at an entry point of the laser beam into the body of water is determined from at least three measurement points of the water surface, wherein a local entry angle of the laser beam into the body of water is determined from the local inclination and the known direction of the laser beam, and wherein the measurement point of the water bottom is determined as a function of the laser beam direction, the local inclination, and the optical refraction due to the corresponding entry angle of the laser beam.