SPACE-BORNE ALTIMETRY APPARATUS, ANTENNA SUBSYSTEM FOR SUCH AN APPARATUS AND METHODS FOR CALIBRATING THE SAME

摘要

The present invention is directed to a space-borne altimetry apparatus having a first receiving antenna, pointing to outer space, for receiving at least one signal emitted by a remote satellite emitter via a direct path; a second receiving antenna, pointing to the Earth, for receiving said signal via an indirect path including a reflection from the Earth surface; and a signal processing means for computing a distance of the apparatus from a specular reflection point of the signal on the Earth surface by cross-correlating the signals received by said first and second antennas; wherein both the first and second receiving antennas are high-gain steerable antennas; and wherein the apparatus may also include antenna control means for steering at least one receiving lobe of the first antenna toward the remote satellite emitter, and at least one receiving lobe of the second antenna toward a specular reflection point on the Earth surface.