RF Jammer

Roadside bombs and other improvised explosive devices (IEDs) continue to account for a high percentage of military fatalities in Iraq and Afghanistan. This year alone, 158 of the 283 battlefield casualties among coalition soldiers in Afghanistan have been attributed to IEDs. These grim statistics, along with loss of civilian life and property damage, are driving a shift in focus from mitigating the effects of an explosive device detonation, such as the use of armor plating, to also neutralizing the threat prior to detonation. As the technology utilized by militants becomes more advanced, the field of electronic warfare provides the means to neutralize the threat posed by radio-controlled improvised explosive device (RCIED) detonation.

An RF jammer works by the prevention or disruption of a broadcast RF signal. If the jamming device can transmit a more powerful signal on the same frequency as the detonating transmitter, the threat is neutralized for the duration of the transmission of the jamming signal.

By permanently transmitting at a sufficient power level, an RF jammer effectively neutralizes the threat of RCIED detonation within its effective radius. There are several jamming methods used, depending on the type of RCIED.
Active bomb jammers transmit continuously, whereas reactive bomb jammers scan a range of frequencies and utilize detection algorithms to identify suspect signals. When a threat is identified, a reactive jammer focuses its signal against the perceived threat, allowing more power to be focused on the target frequency than can be achieved with an active jammer. Thus, the reactive type more suited to countering threats where the detonating transmitter is operates at power levels greater than 1 watt.

Broadband jammers are highly effective RF jammers with a wide range of operating frequencies, typically 20MHz up to 6GHz; representing the full range of transmitter and receiver technology available to militants, from radio controlled toy cars and citizens’ band radios, up to high frequency satellite phones. Utilizing barrage jamming, where a range of frequencies are transmitted simultaneously, or sweep jamming, where the transmission cycles through a range of frequencies rapidly, broadband jammers are typically deployed to counter low power RCIED transmitters operating under one watt. This is due to the broadband jammer’s available transmission power being spread over multiple frequencies, lowering its RCIED suppression capabilities. Sweep jamming helps to keep transmitter power high as the unit cycles through the programmed frequency range, but there is the possibility of a detonating signal slipping through between sweeps.

High power reactive jammers are typically coupled with active jammers to provide the maximum coverage against high and low power RCIED signals as the power of most RCIED transmission signals is below that of the surrounding electromagnetic environment.

Does your university have rf jamming devices?

Math and English: what are the three core subjects on which have boards, the 9.5 million candidates of the entrance exam for universities, which plays the role of BA in most countries.

But the review, deemed particularly stressful and selective – typically only 60% of candidates receive a diploma and a grade determines entry into a reputable university or otherwise – has also been a learning point for highly organized group of cheaters; six of them were arrested just before the start of the tests, the news reports.

With radio frequency transmitters, the cheaters had to blow out the correct answers to candidates who sought their services. They are monetizing this “service” for a hefty fee, according to police reports, and had already pocketed accomplices from interested candidates.

SUB-GIFTED HIGH-TECH

The press regularly reports to the evolution of cheating techniques, reports today’s paper. Glasses with headphones, watches can receive messages …: Arsenal cheats gladly takes advantage of advances in electronics and miniaturization to use to do well on the exams.

The authorities have taken drastic measures this year to track down cheaters to preserve the reputation of a diploma as one of the few prizes of upward social mobility. Some examination rooms have been equipped with metal detectors and radio jamming devices, while in the province in the Northwest, hit last year by a scandal over cheating, 3000 police were mobilized for monitoring of future graduates.

Last year, thirty-four people were arrested in the province for providing equipment to cheat candidates. Gadgets worthy of the film The Sub-Gifted ranged from gum hiding an LCD to the headset, via a rule incorporating a screen connected to the Web.

But if the high-tech cheating worries the authorities, the number of candidates involved remains low. Each year, suspicions of corruption are also testing centers, but the number of establishments involved is impossible to quantify.

The present invention retrieves itself to a procedure of antimissile protections of vehicles as well as to an RF Jammer device of implement of this procedure.

The invention is relating to the vehicle mounted jammer protection such as of the aircraft (had, helicopters) or earthly vehicles (trucks, tanks) against the missile threat to guidance infrasonic, TV or electromagnetic, and in a manner more general, equipped missiles of a device of designation of objective, or associated to such a device.

The portable missiles, operated by a single individual, are a considerable threat, so on the military plan that lives to screw of an eventual terrorist usage.  The well known example of the shooting of a missile IR on a big civil aircraft carrier to the take-off by an isolated actor placed to the neighborhood of an airport, illustrates this threat type.

In order to fight against this threat type, the current solutions are based on the principle of detection of the threat with treatment by fitting countermeasures.  The detection is realized by systems set up (based to the ground) or taken on the vehicles in movement and consists is in a detection radar, is in detection view.  This detection uses principles of trajectory to release countermeasures such as of the maneuvers of excitement, of the delude active or passive radars of the delude passive or active infrastructure of the lasers, antimissile munitions, …

The current solutions present the following inconveniences.  The recourse to a detection principle then countermeasure on the threat imposes a reaction time very runs in comparison with the time of minimal flight of a missile, the lengths of flights of the missiles being short.  This constraint imposes a rate of false ones alarm potentially student.  If the system is embarked on an aircraft or a vehicle, the cost and the weight of the system are preponderant factors in the choice of the solution.

Elsewhere, the integration of radio jamming systems of countermeasure tourniquet on float them already operational can be done by the addition of a “pod” removable that can modify the aerodynamic characteristics of the carrier, which has an incidence on the consumption.  The recourse to the delude, such as cartridges of scrambling infrasonic, is impossible nearby of the civil airports, owing to the inherent risks of fire to such devices.  The recourse to the jammers lasers required a system of pictographic missile/target guaranteeing the point age of the beam in the field of view of the missile.  The presents invention has for object a procedure of antimissile protections of vehicles that has a reaction time very runs without practically no false one alarms and not necessitating the recourse to means such as of the delude aforementioned type or to jammers lasers classical, while offering a protection the possible better one.  The presents invention has equally for object a device of antimissile protections of vehicles that is the simplest the lightest and most possible most economical one.

The procedure of antimissile protections of vehicles in accordance with the invention are characterized in that one creates at least a curtain of filaments of plasma between these vehicles and it no probable shooting of these missiles, this curtain being destined to blind the device of designation of objective of the missiles.

According to an advantageous characteristic of the invention, the plasma filaments are tightened in a manner to produce an ionized tablecloth almost continues.  According to an advantageous characteristic other of the invention, the plasma curtain is created by a beam laser sweeping a corresponding portion of the space in a perpendicular noticeably plan to the probable trajectory of the missiles to the approach the threatened vehicles.

The device of antimissile protections in accordance with the invention is characterized in that it includes a laser impulsion, a device of check of the spectral phase of the laser and a device of spatial sweeping

Allowing orienting the beam laser according to different directions of the space.  The presents invention more better will be understood to the reading of the detailed description of a method of realization, take by way of non restrictive example and illustrated by the annexed drawing, on which:

- 1 is a simplified outline of an example of device of implement procedure of the invention for an airport protection, his superior party being an over view, and his inferior party a view aside,

- 2 is a simplified outline of another example of device of implement procedure of the invention for an airport protection, his superior party being a view of over, and his inferior party a view aside,

- 3 is simplified of an example of device of implement procedure of the invention for a protection of an airplane in flight,

- 4 is simplified of an example of device of implement procedure of the invention for a protection of an earthly vehicle his inferior party being an over view, and his superior party a view full-face.

In a manner summarized, the invention consist in to realize a plasma curtain using a willing laser on a special zone.  The protection screen formed by this curtain has for objective to prevent the locking of the devices directorates of the missiles on the target.  The invention uses the property of the impulses lasers extremist-current (of a preferably inferior length to 10 ps) to create filaments of plasma by ionization of the air.  In fact, an impulse laser that propagates itself in the atmosphere can be focused in a given point of the space to create in this point a plasma.  It produces himself then in the extension of this point a directly in line with filament propagation of the beam.  This filament propagates itself on of long distances

(Until several kilometers) and possesses similar property of dismissive to the one of a black body carried to high temperature (> 1000 0 K indeed 3000K).  This filament typically has a diameter of some hundreds of microns.  The laser implemented by the invention is a laser impulsion, having a frequency jamming of repetition of the impulses for example understood between 10 Hz and 10 kHz lasted It impulses of this laser is most possible briefest, for example inferior to 10PS.  In fact, more the length of these impulses is long, more the laser must deliver energy.  This energy favorably is understood between 1MJ and several Joules, his value being function in particular of the length of the impulses and characteristics of the filaments that one desires to produce.  The value of the length of wave laser is not critical.  One uses favorably the available lasers in the commerce, for example solid environments of the type Titanium Sapphire that present a wide ghost of fluorescence to the neighborhood of the length of wave of 800NM, which allows delivering impulses subconsciousness (“microseconds”) while exploiting the technology CPA (“Chirp Draws To Amplify”).

The creation of the screen of protection is done as follows.  One does to undergo to the beam of go out of the laser compulsion a sweeping in a plan, to create a filament curtain that one desires to interpose between the vehicle to protect and the directorate or system of aim of a missile.  The filaments being missions in the spectral bands of the sensors of which generally are provided the autodidact (or devices of designation of objective) missiles, it produces himself an effect of blind and of masquerade of the line of aim.  The screen formed by this filament curtain can be used is to prevent the shooting by neutralization of the acquisition, is in scrambling of the missile in flight by masque of the target and similar effect to the one of delude.  The device of the invention, simply person known as below

The sensor 720 may also communicate with the receiver bandwidth, selectable for each page. Controller 730 can receive data from various sources (source across 750, 760, speed sensor, sensor 770 Bluetooth and other functions 780) and lassitude of an offense. Controller 730 can control the operation of encryption device 740 and may also change antenna of 710 between modes of transmission and reception.

Controller 730 can control operation of the parties that the power management Jammer. Controller 730 can also catch a plane adjuster attenuator 710 730 drivers, hardware, software and firmware. Controller 730 can be programmed by a technician. Some controllers can be programmed by the user. The user can program the controller running on a mobile device. Jammer behaves essentially the laser such as describes above, one

Device of check of the spectral phase of this laser and a device of spatial sweeping of the beam of this laser.  The allowing realization of a laser to create a filament of ionized air, as well as the check of the spectral phase of his beam regarding to check the length of this filament being known in itself, will not be described more in detail.  A device of check of the spectral phase of a beam laser is known for example according to the French patent 2 751 095.  One will note only that the device of deflection of a beam laser equally being known in itself, the presents description retrieves itself more particularly to the combination of these various means for the realization of a screen of filaments and to his implement for the vehicle protection.

One has represented schematically in figure 1 a first example of application of the invention for the airport protection, in which the device of the invention is used to create a screen under the plans of descent or of amount of the aircraft.  This has for effect to block the line of aim of an eventual directorate of ready missile to be pulled quotation or in the rear sector of the aircraft.  The device is disposed at the end of track and not at all in elevation with a lightly inferior angle to the one of the trajectories followed by the aircraft.  A sweeping in azimuth allows creating the filament curtain.  On this figure 1, the superior party is a view of over of an example of a configuration of a device of protection of an airport of the invention, while the inferior party of this face is a view aside of this same configuration.

a site for helicopter, the same principle is kept to protect the corridors of approaches or of departures down with altitude of the helicopters.

It is so possible to use a principle of movement of the curtain of filaments that follows the trajectory of the vehicle to protect.  This followed one can be generated at the level of the laser by check of the distance of vocalization and/or by check of the spectral phase of the impulses in order compensation the effect of dispersion of the environment of propagation that is the atmosphere.  One has represented chastisement in figure 3 an example of implement of a such proceeded in a similar airport to the one of the figure 2, and behaving the tracks 11 and 12.  One simplified a zone of movable protection only for a jammer 14A (similar to the jammer 14, but being able to produce a zone of movable protection).  It is well heard that all the others jammers 13A, 15A and 16A (respectively similar to the jammers 13, 15 and 16) can present the same characteristics that the jammer 14A.  One simplified different successive positions 21 to 24 of the zone of protection created by the jammer 14A, this protection zone moving itself in synchronize with the movements of the aircraft to protect, favorably in a manner that the aircraft is noticeably close to the center of the zone of protection to every instant.