A synthetic aperture radar method for remote sensing of the surface of the Earth by means of a radar device (1, 2) on a flying object moving in an azimuth direction (x) above the surface of the Earth, wherein the radar device (1, 2) comprises an array of antenna elements for transmitting radar pulses in a transmitting operation and for receiving radar echoes of said radar pulses reflected at the surface of the Earth in a receiving operation, wherein the radar device (1, 2) is configured such that, in an SAR normal operating mode for obtaining SAR images, simultaneously a plurality of radar echoes (EC1, EC2, EC3) from different radar pulses (RP1, RP2, RP3) are received and are separated from one another by means of digital beamforming, wherein a calibration mode is carried out in which - the transmission of the radar pulses in the transmitting operation is carried out with a predetermined pulse repetition rate so that only echo signals of a single radar echo are received by all antenna elements of the array at the same point in time in the receiving operation; characterized in that - in the receiving operation, the echo signals are recorded in a plurality of receiving channels (CH i, CH j, CH k), wherein a different antenna element is assigned to a respective receiving channel (CHi, CHj, CH k), and in the respective receiving channel (CH i, CH j, CH k) the echo signals received by the assigned antenna element are digitized and directly stored independently of the other receiving channels (CH i, CH j, CH k), thereby obtaining digitized radar data (RD i, RD j, RD k) for each receiving channel (CH i, CH j, CH k); - the digitized radar data (RD i, RD j, RD k) of the respective receiving channels (CH i, CH j, CH k) are further processed to determine a set of calibrated parameters (wi) of the radar device (1, 2) for the SAR normal operating mode, wherein the set of calibrated parameters (wi) comprises calibrated coefficients for combining received echo signals of individual antenna elements during the digital beamforming in the SAR normal operating mode for obtaining SAR images. - the transmission of the radar pulses in the transmitting operation is carried out with a predetermined pulse repetition rate so that only echo signals of a single radar echo are received by all antenna elements of the array at the same point in time in the receiving operation; characterized in that - in the receiving operation, the echo signals are recorded in a plurality of receiving channels (CH i, CH j, CH k), wherein a different antenna element is assigned to a respective receiving channel (CHi, CHj, CH k), and in the respective receiving channel (CH i, CH j, CH k) the echo signals received by the assigned antenna element are digitized and directly stored independently of the other receiving channels (CH i, CH j, CH k), thereby obtaining digitized radar data (RD i, RD j, RD k) for each receiving channel (CH i, CH j, CH k); - the digitized radar data (RD i, RD j, RD k) of the respective receiving channels (CH i, CH j, CH k) are further processed to determine a set of calibrated parameters (wi) of the radar device (1, 2) for the SAR normal operating mode, wherein the set of calibrated parameters (wi) comprises calibrated coefficients for combining received echo signals of individual antenna elements during the digital beamforming in the SAR normal operating mode for obtaining SAR images.