5. Conclusion

Threats are increasingly varied (particularly in the field of drones), discreet or even stealthy, fast, and capable of sudden maneuvers. Moreover, theaters of operation are evolving, from land-based "pitched battles" to "diffuse" theaters, and from naval battles to near-coastal operations.

In this complex environment, radars are evolving in six main directions.

• The use of passive radars, which exploit the emissions of other users of the electromagnetic spectrum, turning the disadvantage of spectrum congestion into an operational advantage: discreet, they can "see without being seen".

• Intelligent" use of radar resources. Cognitive radars" exploit not only the data they have acquired on the operational terrain (terrain reflectivity, target density, trajectories...