Method for jamming synthetic aperture radars and associated device

A method for jamming at least one SAR-type airborne radar implemented by a radar-jamming device comprising a group of at least two cooperating units surrounding an area on the ground to be protected, at least two units of said group providing a radar-detection function and at least one unit of said group providing a radar-jamming function, each unit providing the radar-detection function comprising a receiving and processing module configured to analyze the received signals, each unit providing the radar-jamming function being configured to generate and to transmit jamming signals, each unit being interlinked by at least one two-way data link and being synchronized by a common clock, said method being wherein it comprises a step (Etp10) of identifying the signals received by the receivers and whether said received signals correspond to synthetic aperture radar signals:

• a step (Etp20) of characterizing the received SAR signal over a predetermined duration that is shorter than the duration of a recurrence of the SAR signal;
• a step (Etp30) of computing a filter adapted to the pulses of the received SAR signal;
• a step (Etp40) of carrying out pulse compression of the received SAR signal on each recurrence using said adapted filter, making it possible to obtain the phase in the distance boxes, thereby making it possible to obtain the Doppler history linked to the movement of the radar carrier;
• a step (Etp50) of iteratively periodically characterizing the received signal over a predetermined duration that is longer than a recurrence of the SAR signal so as to establish, from one recurrence to the next, the speed of movement of the radar and the distance between said radar and the area to be protected;
• a step (Etp60) of computing the jamming signals to be transmitted for each point of the area to be protected so as to jam the SAR radar coherently on the distance axis and on the Doppler axis;
• a step (Etp70) of transmitting the computed jamming signals.