Optronic system for a countermeasure unit and method to optically communicate

1. An optronic system for a countermeasure unit to optically communicate with another communication terminal, the countermeasure unit comprises a laser beam source and a directing device for a laser beam of the laser beam source, the optronic system comprising:

a detector configured to detect an incoming communication in an incoming signal;

a modulation unit configured to demodulate the incoming signal or cause a modulation of an outgoing laser beam by a coherent modulation in which an amplitude and a phase is modulated simultaneously; and

a control unit configured, in response to the detected incoming communication, to control the modulation unit to demodulate the incoming signal or to modulate the outgoing laser beam to enable an optical communication via the laser beam source of the countermeasure unit,

wherein the detector includes a retroreflection detector, the retroreflection detector being configured:

to detect signals reflected by the other communication terminal due retroreflections,

to initiate the optical communication based on detected retroreflections, the optical communication being performed via the laser source of the countermeasure unit, and

to keep alive a laser communication path by tracking retroreflections.

2. The system according to claim 1 , wherein the countermeasure unit further comprises a tracking camera configured to capture images from a scene with the other communication terminal,

the control unit being further configured to control the tracking camera to direct the laser beam during the optical communication by stabilizing the laser beam directed to the other communication terminal.

3. The system according to claim 1 , wherein the directing device of the countermeasure unit is configured to track the object of threat,

the control unit being further configured to control the directing device to adjust a direction of the outgoing laser beam onto a moving other communication terminal.

4. The system according to claim 1 , wherein the countermeasure unit or the detector is configured to detect a threat from the object,

the control unit being further configured to interrupt the optical communication upon a detection of the threat and to trigger countermeasures for dazzling or jamming the object of threat.

5. The system according to claim 1 , wherein

the detector includes a laser communication detector, the laser communication detector including a local oscillator for coherent detection and being configured to detect a modulated incoming communication beam.

6. The system according to claim 1 , wherein the modulation unit is configured to modulate the outgoing laser beam during optical communications using different modulation formats when compared to using the laser beam during countermeasures, the different modulation formats include coherent or non-coherent modulations.

7. The system according to claim 6 , wherein the modulation unit is configured to use a phase modulation format during optical communications.

8. A countermeasure system for jamming or dazzling a target acquisition, the countermeasure system comprising:

a laser beam source configured to generate a laser beam;

a directing device for directing the laser beam on a target or on another communication terminal of a laser communication; and

an optronic system according to claim 1 .

9. The countermeasure system according to claim 8 , wherein the laser beam source is configured to generate the laser beam for the optical communication with a wavelength in one of the following frequency bands:

short wave infrared, SWIR, comprising wavelengths between 1.4 to 2.0 micrometers,

extended short wave infrared, eSWIR, comprising wavelengths between 2.0 to 2.5 micrometers,

mid infrared, MIR, comprising wavelengths between 3.0 to 5.0 micrometers.

10. The countermeasure system according to claim 8 , further comprising countermeasure modulation unit configured to cause a modulation of an outgoing laser beam to dazzle or to jam the object of threat as a countermeasure.

11. A vehicle with the countermeasure system according to claim 8 .

12. A method for controlling a countermeasure unit to optically communicate with another communication terminal, the countermeasure unit comprising a laser beam source and a directing device for a laser beam of the laser beam source, the method comprising:

detecting an incoming communication in an incoming signal; and

demodulating the incoming signal or causing a modulation of an outgoing laser beam by a coherent modulation in which an amplitude and a phase is modulated simultaneously to enable the optical communication via the laser beam source of the countermeasure unit,

wherein detecting includes:

detecting signals reflected by the other communication terminal due to retroreflections,

initiating the optical communication based on detected retroreflections, the optical communication being performed via the laser source of the countermeasure unit, and

keeping alive a laser communication path by tracking retroreflections.

13. The method according to claim 12 , further comprising:

switching between a laser communication mode and a countermeasure mode,

wherein in the laser communication mode the laser beam source is caused to modulate the outgoing laser beam to transmit information and in the countermeasure mode the laser beam source is caused to modulate the outgoing laser beam to dazzle or to jam an object of threat as a countermeasure.