Method for confusing the electronic signature transmitted by a radar, and transmission/reception device suitable for implementing same

1. A method for confusing the electronic signature of a signal transmitted by a radar, comprising the generation by the radar of a plurality of pulses, wherein the method comprises a step of modulation, in the pulse, of the polarization of the transmitted signal, according to two orthogonal or opposite polarizations, the modulation of the polarization being performed according to a predetermined modulation code, the modulation code being temporally inverted from one pulse to the next.

2. The method according to claim 1 , wherein the modulation code alternately switches the polarization from left-hand circular to right-hand circular.

3. The method according to claim 1 , wherein the modulation code alternately switches the polarization from left-hand oblique linear to right-hand oblique linear.

4. The method according to claim 1 , wherein the modulation code comprises, to within one moment, as many moments for both orthogonal or opposite polarizations.

5. The method according to claim 1 , wherein the modulation code is a seven-moment Barker code.

6. A transmission/reception device configured to implement the confusion method according to claim 1 , the transmission/reception device comprising a single reception channel suited to a rectilinear polarization corresponding to one of the two polarization components of the polarization of the transmitted signal.

7. An antenna comprising a plurality of devices according to claim 6 , the antenna being of the electronic scanning type.

8. A transmission/reception device configured to implement the confusion method according to claim 1 , and comprising:

a first reception channel suited to a first rectilinear polarization corresponding to a first polarization component (Ex) of the polarization of the transmitted signal; and

a second reception channel suited to a second rectilinear polarization corresponding to a second polarization component (Ey) of the polarization of the transmitted signal;

a correlator common to the first reception channel and to the second reception channel, and configured to perform a filtering suited to the modulation code.

9. The device according to claim 8 , wherein the correlator comprises:

a first shift register composed of delay cells ( 106 0 , . . . , 106 N-1 ) applied to the first reception channel, and a second shift register composed of delay cells ( 107 0 , . . . , 107 N-1 ) applied to the second reception channel, the number of delay cells of each shift register being equal to the number N of moments of the modulation code;

a first series of N phase compensation cells ( 108 0 , . . . , 108 N-1 ), each phase compensation cell ( 108 0 , . . . , 108 N-1 ) of the first series being connected to a delay cell ( 106 0 , . . . , 106 N-1 ) of the first shift register, and configured to modulate a sample stored in the delay cell by a phase that is identical or conjugate relative to the phase of the moment of same rank of the modulation code applied to the first polarization component;

a second series of N phase compensation cells ( 109 0 , . . . , 109 N-1 ), each phase compensation cell ( 109 0 , . . . , 109 N-1 ) of the second series being connected to a delay cell ( 107 0 , . . . , 107 N-1 ) of the second shift register, and configured to modulate a sample stored in the delay cell by a phase that is identical or conjugate relative to the phase of the moment of same rank of the modulation code applied to the second polarization component;

a set of summers ( 110 0 , . . . , 110 N-1 ), each summer ( 110 0 , . . . , 110 N-1 ) being coupled to a phase compensation cell ( 108 0 , . . . , 108 N-1 ) of the first series and to a phase compensation cell ( 109 0 , . . . , 109 N-1 ) of the second series of same rank;

a convolution circuit, configured to convolute a signal from the summers ( 110 0 , . . . , 110 N-1 ) with a temporal replica of the pulse of the transmitted signal.