Method for georeferencing of a digital elevation model

A method for georeferencing a digital elevation model of a surface of Earth, the method comprising a first step of:

• obtaining at least two synthetic aperture radar images which are reference radar images, wherein a footprint of each of the reference radar images includes a common zone common to an overlap zone of overlap with a footprint of at least one other of the at least two reference radar images and with the digital elevation model;
• the method further including, for each of the reference radar images, steps of:
• selecting at least one area of interest on the common zone;
• calculating a simulated radar image on the at least one selected area of interest from acquisition parameters of the reference radar images;
• estimating a geometric offset between the simulated radar image and at least one of the reference radar images;
• the method further comprising:
• selecting at least one referencing point on the at least one selected area of interest from the digital elevation model, the at least one referencing point including terrain coordinates in a frame of reference of the digital elevation model,
• projecting said at least one referencing point into each of the at least two reference radar images by a radar projection function relating to each of the reference radar image to obtain at least one radar link point relating to each of the at least two reference radar images;
• correcting the at least one radar link point of each of the at least two reference radar images by applying said geometric offset estimated for each of the reference radar images to obtain at least one corrected radar link point relating to each reference radar images;
• calculating reset terrain coordinates of the at least one referencing point by applying a triangulation process implementing said at least two reference radar images from the at least one corrected link point relating to each reference radar image;
• and
• georeferencing the digital elevation model by transformation as a function of deviations between the reset terrain coordinates and the terrain coordinates in the frame of reference of the digital elevation model.