Calibration method and system

The present invention concerns a method for calibrating an array of receivers (ri), each receiver being configured for receiving a signal transmitted by at least one transmitter (si), and echoes of the transmitted signal as reflected by one or more reflective surfaces (w), said method comprising the following steps: sorting said echoes, by assigning each echo to a reflective surface or to a combination of reflective surfaces (w) calibrating said array of receivers (ri) based on said sorting.