Patent ID: 8405539

Claim:
A method for causing a target ( 2 ) to provide respective target information, the method comprising: equipping the target ( 2 ) with an identification device ( 3 ); receiving, by the identification device ( 3 ), a radar signal (RS) transmitted by a synthetic aperture radar system ( 1 ) and comprising at least one radar pulse of a given pulse duration (DSAR); processing, by the identification device ( 3 ), the incoming radar signal (RS) to obtain a processed radar signal (ES), wherein processing the received radar signal (RS) comprises modulating the received radar signal (RS) with a modulating signal (MODS) including target information comprising an identification code (ID) unequivocally identifying the target ( 2 ); transmitting the processed radar signal (ES) by the identification device ( 3 ); receiving, by the synthetic aperture radar system ( 1 ), a radar echo signal (RES) comprising the processed radar signal (ES); and processing the radar echo signal (RES), by the synthetic aperture radar system ( 1 ), to locate the target ( 2 ); wherein processing the radio echo signal (RES) comprises demodulating the radar the radio echo signal (RES) to extract therefrom the identification code (ID) to identify the target ( 2 ); wherein: the target information comprises at least one status message (MSG) relative to a status of the target ( 2 ); processing, by the identification device ( 3 ), the received radar signal (RS) comprises: encrypting the target information (ID, MSG) by a programmable encryption key, and modulating the received radar signal (RS) with the modulating signal (MODS) thereby obtaining a modulated signal (MS), said modulating signal (MODS) comprising: the encrypted identification code (ID) coded by a respective first sequence of a given first number (NID) of binary digits, each of given first duration (DID), and the encrypted at least one status message (MSG), each coded by a respective second sequence of a given second number (NMSG) of binary digits, each of a given second duration (DMSG), wherein said first digit duration (DID) and said second digit duration (DMSG) are such that a total duration of the binary digits coding the encrypted target information (ID, MSG) does not exceed the given pulse duration (DSAR): and processing, by the synthetic aperture radar system ( 1 ), the radar echo signal (RES) comprises: demodulating the radar echo signal (RES) by performing a succession of matched-filter demodulations of respective successive portions of the radar echo signal (RES) defined by the digit durations (DID, DMSG)of all the binary digits coding the encrypted target information (ID, MSG), and decrypting the extracted, encrypted target information (ID, MSG) by said programmable encryption key thereby obtaining the identification code (ID) and the at least one status message (MSG).