Patent ID: 8059025

Claim:
An altimetry method for determining an elevation profile of a portion of the Earth surface (ES), comprising the steps of: (a) providing a signal receiver (RX) on a first platform (S 1 ) flying above said portion of the Earth surface, for receiving a temporal series of signals emitted by a second flying platform (S 2 ) and scattered by said portion of the Earth surface; and (b) computing altimetry waveforms, indicative of the elevation profile of said portion of the Earth surface, by processing the received signals; characterized in that said step of computing altimetry waveforms comprises: (b.1.1) determining correlation waveforms (XC) by cross-correlating the received signals with a plurality of locally-generated frequency-shifted replicas of the emitted signals, the frequency shift of each replica corresponding to the average Doppler shift of the signals reflected at a given time by a particular region of the Earth surface; (b.1.2) introducing a Doppler frequency-dependent temporal shift to the correlation waveforms in order to compensate for range delay curvature; and (b2) incoherently summing the temporally shifted correlation waveforms (CXC) corresponding to signals scattered by a same region of the Earth surface at different times during motion of said first platform.