Jamming Devices

One supposes, as that generally could be the case, that an eventual threat of terrorist attack risks producing itself nearby track of envoy and/or of landing 1 of an airport, from the ground and noticeably in a zone where the aircraft are down with or very low altitude.  To protect these aircraft, one disposes directly in line with the track 1, in the extension of his extremity, nearby of this extremity, a radio frequency jammer 2 of which the beam laser, at the time of the functioning of the laser, in rest position 3 (without sweeping), is directed directly in line with this track, to the opposed track, and of which the angle, in elevation, is lightly inferior to the angle of the trajectory of landing 4 aircraft 5.

At the time of the functioning of the jamming device of protection, one does to undergo to the beam laser a sweeping in a plan, in a manner symmetrical noticeably in comparison with the rest position 3.  The plan in which takes place this sweeping is such as his intersection with the ground is perpendicular to the axis of the track 1.

The angle of deflection of the beam laser to assure this sweeping is function, in particular, distance between the rf jammer and the edge 6 of the curtain 7 of filaments of plasma (edge formed by the points of creation of the filaments) and lateral range of the zone 8 where one wants to assure the protection.  One will note that this protection zone lightly is more spread longitudinally and laterally than the curtain of filaments on account of the fact that Péblouissement by a filament of plasma of a device of designation of objective of missile is provoked in a wider space than the diameter of this filament.  The frequency of this sweeping is function of the length of life of the filaments (some hundreds of microseconds to some tens of microseconds, indeed some hundreds of microseconds, according to the ionization of the environment in which are created these filaments).  She is for example of some kHz.  Thus, the plasma screen 6 permit to protect the aircraft when they are nearby track 1 (to missile reach) by report to pulled missiles since a shooting step 9 situated nearby track 1, the line of shooting aim coming from this shooting step (and going through a point marked by a cross 10 on the drawing) being able to be to have directed towards any not at all of the protected zone 8.

Well heard, to assure a better protection of airport, it is advantageous to use in a manner crossed multiple jammers willing to the extremities of the tracks of envols and/or to different distances of these extremities.  A simplified example of a protection of airport was represented in figure 2.  On this figure 2, one has represented schématiquement two tracks 1 that s’intersectent itself and that have different orientations.  Jammers 13 to 16 are disposed close to the extremities of the tracks 1 1 and 12.

Respectively, according to a similar disposal to the one of the jammer 2 of the figure 1.  These broadband jammers 13 to 16 create protected zones 17 to 20, respectively, similar to the zone 8 of the figure 1.  In the case of Well heard, as simplified in figure 4, the jammer of the invention is applicable in the case of the protection of a convoy 25 of movable ones to the ground (trucks of transportation, for example) lives to screw of a threat ground ground (a fight tank 26, for example).  In this case, the geometry of the curtain of plasma 27 generated one on board of at least the one of the vehicles (for example by the jammer 28 willing one in the tail vehicle 29) presents itself under the vertical form of a plan interposed between the body of the convoy 25 and the threat 26.

According to another method of realization of the invention, one begins the plasma of the filaments of the curtain of filaments using a laser impulsionnel femtoseconde of the type describes above, and as soon as priming took place, instead of maintaining the ionization of these filaments using the same laser femtoseconde, one maintains it using a laser of power of the type impulsionnel (of some Watts to some kilowatts, according to the length of its impulses), producing impulses lasers comparatively long (of a length of several Nanoseconds to several microseconds), of which the wave length is not very critical (she can be situated in the infrarouge, the visible or the
ultraviolet one).  An advantageous application of the procedure of the invention consist in to generate from afar a movable potential object in the space, this object being able to be is a plasma curtain is a plasma filament.

This potential object can have the dimensions and the earthly habitual vehicle form or aerial, and its movements are able, owing to his strong luminosity, is to simulate the trajectory of a vehicle in the space, is to serve as delude able to attract the sensors optroniques of autodirecteurs.  Thus, one can replace the described protection above of the real vehicles or to complete it, while attracting the missiles towards these potential objects.  The principal advantages of the procedure of the invention and of his device of implement are that it does not use any detector of missile, and is not therefore constrained by a buckle of quick reaction, that it contributes to delude the missiles to autodirecteurs optroniques and that it does not produce any chemical, mechanical residue or generally of materials.