WO1994017505A1 - Tamperproof radio anti-jamming device for trespass monitoring systems - Google Patents

Tamperproof radio anti-jamming device for trespass monitoring systems Download PDF

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Publication number
WO1994017505A1
WO1994017505A1 PCT/FR1994/000076 FR9400076W WO9417505A1 WO 1994017505 A1 WO1994017505 A1 WO 1994017505A1 FR 9400076 W FR9400076 W FR 9400076W WO 9417505 A1 WO9417505 A1 WO 9417505A1
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WO
WIPO (PCT)
Prior art keywords
alarm
jamming
detector
signal
interference
Prior art date
Application number
PCT/FR1994/000076
Other languages
French (fr)
Inventor
Paul Edouard Bouquin
Alain De Salaberry
Original Assignee
Paul Edouard Bouquin
Alain De Salaberry
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Paul Edouard Bouquin, Alain De Salaberry filed Critical Paul Edouard Bouquin
Priority to EP94905142A priority Critical patent/EP0681723B1/en
Priority to DE69407167T priority patent/DE69407167T2/en
Publication of WO1994017505A1 publication Critical patent/WO1994017505A1/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K3/00—Jamming of communication; Counter-measures
    • H04K3/80—Jamming or countermeasure characterized by its function
    • H04K3/88—Jamming or countermeasure characterized by its function related to allowing or preventing alarm transmission
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B25/00—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems
    • G08B25/01—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems characterised by the transmission medium
    • G08B25/10—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems characterised by the transmission medium using wireless transmission systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K3/00—Jamming of communication; Counter-measures
    • H04K3/20—Countermeasures against jamming
    • H04K3/22—Countermeasures against jamming including jamming detection and monitoring
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K2203/00—Jamming of communication; Countermeasures
    • H04K2203/10—Jamming or countermeasure used for a particular application
    • H04K2203/12—Jamming or countermeasure used for a particular application for acoustic communication

Definitions

  • the present invention relates to an anti-jamming device for intrusion monitoring systems in a room.
  • Such systems generally include a plurality of sensors distributed in the premises to be protected and connected to an alarm signaling central, this being connected for example to sirens, and in certain cases, to a telephone line for transmitting alarms possible at a remote monitoring station.
  • interference detection means consisting in detecting the presence of a permanent signal on the frequency used by the system and in generating a jamming alarm. when such a signal is detected.
  • a solution has also been proposed which consists in having a signal sent regularly by each sensor in the direction of the alarm reporting center. When the control panel no longer receives signals from the sensors, it triggers a jamming alarm.
  • the main object of the present invention is to eliminate these drawbacks. To this end, it provides an anti-jamming device intended to equip an intrusion monitoring system comprising a plurality of sensors connected by radio link to a central alarm signaling member.
  • This device is characterized in that it comprises - an interference emission detector on the frequency used by the sensors to communicate with the central body,
  • an alarm circuit responsible for validating an alarm signal emitted by the jamming emission detector intended for the central organ, following a detection of a jamming signal, if an intrusion is detected by the additional detector.
  • the proposed device combines two techniques: a first technique based on intrusion detection and a second based on interference detection.
  • the interference transmissions will trigger an alarm only if there has been a prior intrusion. In this way, it is impossible to trigger a false alarm from outside the monitored premises. Conversely, any intrusion attempt during a jamming period will be detected by both the additional sensor and the jamming detector, which will inevitably trigger a jamming alarm.
  • the additional detector is an infrasound detector.
  • a signal For interference detection using a receiver tuned to the frequency of the monitoring system, a signal will be considered as a signal interference if its amplitude exceeds a certain threshold for a minimum time.
  • the amplitude threshold of the interference signal to be detected and its minimum duration are adjustable.
  • the infrared detector comprises a transducer sensitive to variations in ambient pressure, and for example, a polarized capacitor transforming into an electrical signal, the pressure waves caused by a displacement of air due to, for example, the opening or attempting to open an exit from the monitored room, normally closed.
  • This detector is connected to a time delay which sends, for an adjustable period, an interference alarm validation signal to the alarm circuit, following detection of an intrusion into said zone.
  • the device is connected to the central organ so as not to risk being disturbed by a possible jamming signal, for example by cable, by a radioelectric link using a frequency other than that used by the system. , or by infrared or ultrasound.
  • the device includes a backup power supply and a transmitter, compatible with the receiver of the central organ, and disposed near the latter, always so that the transmission between the device and the central organ is not disturbed by an interference signal.
  • Figure 1 schematically shows a block diagram of the anti-jamming device coupled to a central alarm signaling device according to a first preferred embodiment of the invention
  • FIG. 2 shows another block diagram of the anti-jamming device according to a second preferred embodiment.
  • FIG. 1 represents the anti-jamming device 10 according to the invention coupled to an alarm signaling center 7 which is connected to a siren 9 and which is connected by radio link to a plurality of sensors 8.
  • the alarm center can be connected to the public telephone network 12 to transmit the alarms to a remote monitoring station.
  • the anti-jamming device 10 comprises a jamming detector 5, an infrared detector 1, a time delay 2 and a module 6 responsible for developing an alarm signal from the signals from time delay 2 and the jamming detector 5.
  • the jamming detector 5 comprises a radio wave receiver 3 tuned to the frequency used by the alarm signaling center 7, for example 224 MHz. This receiver 3 analyzes the level of the signal received and sends a jamming indication to a counter 4 when this level is at least equal to that received by the alarm center 7 from the intrusion detector 8 furthest from the central 7.
  • the time counter 4 sends a signal to the module 6 when the jamming indication which is transmitted to it by the receiver 3 is present for an adjustable duration of, for example, more than 50 seconds over an interval of 1 minute.
  • the jamming detector 5 is associated with an infrasound detector 1 currently marketed for detecting intrusions into a room even if it has several rooms.
  • This infrasound detector 1 includes:
  • - a low-pass filter intended to eliminate all the waves whose frequency is higher than a certain threshold.
  • timer 2 for example, 10 minutes.
  • the module 6 which is connected to both the timer 2 and the time counter 4 allows a jamming alarm signal to be sent when it receives a signal from the time counter 4 for the duration set at the timer 2.
  • an alarm will be triggered if there has been interference less than 10 minutes after an intrusion detection by the infrared detector.
  • This alarm is transmitted by a wired link 11 to the timed input of the alarm center 7.
  • the anti-jamming device 10 is designed so as to be able to supplement already installed surveillance systems.
  • the anti-jamming device 10 is connected by the wire link 11 to a radio transmitter 14 set to the timed input of the alarm center 13, and placed very close to the latter. In this way, the connection between the transmitter 14 and the alarm center 13 is not likely to be disturbed by an interference attempt.
  • the alarm center 13 is connected over the air to the siren 16 and to a telephone transmitter 15. If these two elements are too far from the alarm center 13 to be insensitive to interference, a wired connection may be installed between a radio receiver placed near the control panel and these two elements.
  • the anti-jamming device 10 can also include a saved power supply 17 so that it can operate even in the event of a power cut.

Abstract

A device including a sensor (5) for sensing jamming transmissions on the frequency used by trespass sensors (8) to communicate with a central unit (7), an infrasound sensor (1) separate from the monitoring system for sensing any unauthorized entry into the area in which radio transmissions between the sensors (8) and the central unit (7) take place, and an alarm circuit (6) for enabling the alarm signal output from the jamming transmission sensor (5) to the central unit (7) after a jamming signal is sensed, if the infrasound sensor (1) senses an unauthorized entry. The device thus prevents radio communication between the sensors (8) and the central unit (7) from being jammed.

Description

DISPOSITIF ANTIBROUILLAGE RADIO INFRAUDABLE POUR SYSTEMES DE SURVEILLANCE D'INTRUSIONS. AN INFRAUDABLE RADIO ANTI-JAMMING DEVICE FOR INTRUSION MONITORING SYSTEMS.
La présente invention concerne un dispositif antibrouillage pour les systèmes de surveillance d'intrusions dans un local.The present invention relates to an anti-jamming device for intrusion monitoring systems in a room.
Elle s'applique notamment, mais non exclusivement, aux systèmes de surveillance destinés à protéger des locaux contre les effractions ou les tentatives d'effraction. De tels systèmes comprennent généralement une pluralité de capteurs répartis dans les locaux à protéger et reliés à une centrale de signalisation d'alarmes, celle-ci étant connectée par exemple à des sirènes, et dans certains cas, à une ligne téléphonique pour transmettre les alarmes éventuelles à un poste de surveillance distant.It applies in particular, but not exclusively, to surveillance systems intended to protect premises against break-ins or attempted break-ins. Such systems generally include a plurality of sensors distributed in the premises to be protected and connected to an alarm signaling central, this being connected for example to sirens, and in certain cases, to a telephone line for transmitting alarms possible at a remote monitoring station.
Afin d'éviter d'avoir à poser des câbles pour relier les capteurs à la centrale de signalisation d'alarmes, on a déjà proposé de doter les capteurs de moyens émetteurs radio pour communiquer avec la centrale de signalisation d'alarmes. De tels systèmes présentent le risque d'être brouillés. Il suffit en effet qu'un émetteur soit réglé sur la même fréquence et émette un signal de façon permanente pour empêcher la transmission entre les capteurs et la centrale de signalisation d'alarmes, et rendre ainsi le système de surveillance complètement inefficace.In order to avoid having to lay cables to connect the sensors to the alarm signaling central, it has already been proposed to equip the sensors with radio transmitter means to communicate with the alarm signaling central. Such systems present the risk of being scrambled. It suffices that a transmitter is set to the same frequency and emits a signal permanently to prevent transmission between the sensors and the alarm reporting unit, and thus render the monitoring system completely ineffective.
Pour tenter de résoudre ce problème, on a déjà pensé à doter la centrale de signalisation d'alarmes de moyens de détection de brouillage consistant à détecter la présence d'un signal permanent sur la fréquence utilisée par le système et à générer une alarme de brouillage lorsqu'un tel signal est détecté.In an attempt to resolve this problem, it has already been thought of providing the alarm central station with interference detection means consisting in detecting the presence of a permanent signal on the frequency used by the system and in generating a jamming alarm. when such a signal is detected.
On a également proposé une solution qui consiste à faire envoyer régulièrement un signal par chaque capteur en direction de la centrale de signalisation d'alarmes. Lorsque la centrale ne reçoit plus les signaux émis par les capteurs, elle déclenche une alarme de brouillage.A solution has also been proposed which consists in having a signal sent regularly by each sensor in the direction of the alarm reporting center. When the control panel no longer receives signals from the sensors, it triggers a jamming alarm.
L'inconvénient principal de ces deux solutions provient du fait qu'il n'empêche pas une personne située en dehors des locaux à surveiller de déclencher une alarme de brouillage. La répétition de fausses alarmes de ce type conduit en général l'utilisateur à débrancher le système ou, si cela est prévu, à mettre hors service le dispositif antibrouillage.The main disadvantage of these two solutions comes from the fact that it does not prevent a person located outside the premises to be monitored from triggering a jamming alarm. The repetition of false alarms of this type generally leads the user to disconnect the system or, if provided, to deactivate the anti-jamming device.
La présente invention a principalement pour but de supprimer ces inconvénients. A cet effet, elle propose un dispositif antibrouillage destiné à équiper un système de surveillance d'intrusions comprenant une pluralité de capteurs reliés par voie hertzienne à un organe central de signalisation d'alarmes.The main object of the present invention is to eliminate these drawbacks. To this end, it provides an anti-jamming device intended to equip an intrusion monitoring system comprising a plurality of sensors connected by radio link to a central alarm signaling member.
Ce dispositif est caractérisé en ce qu ' il comprend - un détecteur d'émissions de brouillage sur la fréquence utilisée par les capteurs pour communiquer avec 1'organe central,This device is characterized in that it comprises - an interference emission detector on the frequency used by the sensors to communicate with the central body,
- un détecteur additionnel, distinct du système de surveillance, permettant de détecter toute intrusion dans la zone dans laquelle s'effectuent les transmissions radio-électriques,- an additional detector, separate from the surveillance system, making it possible to detect any intrusion into the area in which the radio transmissions are carried out,
- un circuit d'alarme chargé de valider un signal d'alarme émis par le détecteur d'émissions de brouillage à destination de l'organe central, à la suite d'une détection d'un signal de brouillage, si une intrusion est détectée par le détecteur additionnel.- an alarm circuit responsible for validating an alarm signal emitted by the jamming emission detector intended for the central organ, following a detection of a jamming signal, if an intrusion is detected by the additional detector.
Ainsi, le dispositif proposé réunit deux techniques : une première technique basée sur la détection d'intrusion et une seconde basée sur la détection de brouillage. Grâce à cette combinaison, les émissions de brouillage déclencheront une alarme uniquement s'il y a eu intrusion préalable. De cette manière, il est impossible de déclencher une fausse alarme de l'extérieur des locaux surveillés. Inversement, toute tentative d'intrusion pendant une période de brouillage sera détecté à la fois par le capteur additionnel et par le détecteur de brouillage, ce qui déclenchera inévitablement une alarme de brouillage.Thus, the proposed device combines two techniques: a first technique based on intrusion detection and a second based on interference detection. With this combination, the interference transmissions will trigger an alarm only if there has been a prior intrusion. In this way, it is impossible to trigger a false alarm from outside the monitored premises. Conversely, any intrusion attempt during a jamming period will be detected by both the additional sensor and the jamming detector, which will inevitably trigger a jamming alarm.
Selon une particularité de l'invention, le détecteur additionnel est un détecteur d'infrasons.According to a feature of the invention, the additional detector is an infrasound detector.
Or, à l'heure actuelle, un seul détecteur d'infrasons du type décrit dans le brevet français 85 16234 suffit pour surveiller le volume d'un local pouvant comporter plusieurs pièces. Bien que présentant une source fréquente de fausses alarmes, avec une sensibilité bien réglée, les détecteurs de ce type demeurent excellents pour détecter toute intrusion dans un local.However, at present, a single infrasound detector of the type described in French patent 85 16234 is sufficient to monitor the volume of a room which may include several rooms. Although presenting a frequent source of false alarms, with a well-adjusted sensitivity, detectors of this type remain excellent for detecting any intrusion into a room.
En ce qui concerne la détection de brouillage qui utilise un récepteur calé sur la fréquence du système de surveillance, un signal sera considéré comme signal de brouillage si son amplitude dépasse un certain seuil pendant un temps minimum.For interference detection using a receiver tuned to the frequency of the monitoring system, a signal will be considered as a signal interference if its amplitude exceeds a certain threshold for a minimum time.
Avantageusement, le seuil d'amplitude du signal de brouillage à détecter et sa durée minimale sont réglables.Advantageously, the amplitude threshold of the interference signal to be detected and its minimum duration are adjustable.
En outre, le détecteur d'infrasons comprend un transducteur sensible aux variations de pression ambiante, et par exemple, un condensateur polarisé transformant en un signal électrique, les ondes de pressions provoquées par un déplacement d'air dû à, par exemple, l'ouverture ou la tentative d'ouverture d'une issue du local surveillé, normalement fermé. Ce détecteur est connecté à une temporisation qui envoie, pendant une période réglable, un signal de validation d'alarme de brouillage au circuit d'alarme, à la suite d'une détection d'une intrusion dans ladite zone.In addition, the infrared detector comprises a transducer sensitive to variations in ambient pressure, and for example, a polarized capacitor transforming into an electrical signal, the pressure waves caused by a displacement of air due to, for example, the opening or attempting to open an exit from the monitored room, normally closed. This detector is connected to a time delay which sends, for an adjustable period, an interference alarm validation signal to the alarm circuit, following detection of an intrusion into said zone.
De même, le dispositif est relié à l'organe central de manière à ne pas risquer d'être perturbé par un signal de brouillage éventuel, par exemple par câble, par une liaison radio-électrique utilisant une autre fréquence que celle utilisée par le système, ou encore par infrarouges ou ultrasons. Lorsque l'organe central ne dispose pas d'entrées filaires, le dispositif comprend une alimentation de sauvegarde et un émetteur, compatible avec le récepteur de l'organe central, et disposé à proximité de ce dernier, toujours pour que la transmission entre le dispositif et l'organe central ne soit pas perturbée par un signal de brouillage.Likewise, the device is connected to the central organ so as not to risk being disturbed by a possible jamming signal, for example by cable, by a radioelectric link using a frequency other than that used by the system. , or by infrared or ultrasound. When the central organ does not have wired inputs, the device includes a backup power supply and a transmitter, compatible with the receiver of the central organ, and disposed near the latter, always so that the transmission between the device and the central organ is not disturbed by an interference signal.
Un mode de réalisation du dispositif selon 1•invention sera décrit ci-après, à titre d'exemple non limitatif, avec référence aux dessins annexés dans lesquels :An embodiment of the device according to the invention will be described below, by way of nonlimiting example, with reference to the appended drawings in which:
La figure 1 représente schématiquement un synoptique du dispositif antibrouillage couplé à un organe central de signalisation d'alarmes selon un premier mode d'exécution préféré de 1•invention ;Figure 1 schematically shows a block diagram of the anti-jamming device coupled to a central alarm signaling device according to a first preferred embodiment of the invention;
La figure 2 représente un autre synoptique du dispositif antibrouillage selon un second mode d'exécution préféré.FIG. 2 shows another block diagram of the anti-jamming device according to a second preferred embodiment.
La figure 1 représente le dispositif antibrouillage 10 selon 1'invention couplé à une centrale de signalisation d'alarmes 7 qui est connectée à une sirène 9 et qui est reliée par liaison radioélectrique à une pluralité de capteurs 8. La centrale d'alarmes peut être raccordée au réseau téléphonique publique 12 pour transmettre les alarmes vers un poste de surveillance distant.FIG. 1 represents the anti-jamming device 10 according to the invention coupled to an alarm signaling center 7 which is connected to a siren 9 and which is connected by radio link to a plurality of sensors 8. The alarm center can be connected to the public telephone network 12 to transmit the alarms to a remote monitoring station.
Le dispositif antibrouillage 10 comprend un détecteur de brouillage 5, un détecteur d'infrasons 1, une temporisation 2 et un module 6 chargé d'élaborer un signal d'alarme à partir des signaux issus de la temporisation 2 et du détecteur de brouillage 5.The anti-jamming device 10 comprises a jamming detector 5, an infrared detector 1, a time delay 2 and a module 6 responsible for developing an alarm signal from the signals from time delay 2 and the jamming detector 5.
Le détecteur de brouillage 5 comprend un récepteur d'ondes radioélectriques 3 accordé sur la fréquence utilisée par la centrale de signalisation d'alarmes 7, par exemple 224 MHz. Ce récepteur 3 analyse le niveau du signal reçu et envoie à un compteur 4 une indication de brouillage lorsque ce ι niveau est au moins égal à celui que reçoit la centrale d'alarmes 7 en provenance du détecteur d'intrusion 8 le plus éloigné de la centrale 7.The jamming detector 5 comprises a radio wave receiver 3 tuned to the frequency used by the alarm signaling center 7, for example 224 MHz. This receiver 3 analyzes the level of the signal received and sends a jamming indication to a counter 4 when this level is at least equal to that received by the alarm center 7 from the intrusion detector 8 furthest from the central 7.
Par ailleurs, le compteur de temps 4 envoie un signal vers le module 6 lorsque l'indication de brouillage qui lui est transmise par le récepteur 3, est présente pendant une durée réglable de, par exemple, plus de 50 secondes sur un intervalle de 1 minute.Furthermore, the time counter 4 sends a signal to the module 6 when the jamming indication which is transmitted to it by the receiver 3 is present for an adjustable duration of, for example, more than 50 seconds over an interval of 1 minute.
Au détecteur de brouillage 5 est associé un détecteur d'infrasons 1 actuellement commercialisé pour détecter les intrusions dans un local même si ce dernier comporte plusieurs pièces.The jamming detector 5 is associated with an infrasound detector 1 currently marketed for detecting intrusions into a room even if it has several rooms.
Ce détecteur d'infrasons 1 comprend :This infrasound detector 1 includes:
- un transducteur qui transforme les ondes sonores assimilables à des variations de pression en un signal électrique,- a transducer which transforms sound waves comparable to pressure variations into an electrical signal,
- un condensateur polarisé délivrant une tension propor- tionnelle à la pression, et- a polarized capacitor delivering a voltage proportional to the pressure, and
- un filtre passe-bas destiné à éliminer toutes les ondes dont la fréquence est supérieure à un certain seuil.- a low-pass filter intended to eliminate all the waves whose frequency is higher than a certain threshold.
II est conçu de manière à ce que toute intrusion déclenche la temporisation 2 pendant une durée fixée et réglable, par exemple, 10 minutes.It is designed so that any intrusion triggers timer 2 for a fixed and adjustable duration, for example, 10 minutes.
Le module 6 qui est relié à la fois à la temporisation 2 et au compteur de temps 4 permet d'envoyer un signal d'alarme de brouillage lorsqu'il reçoit un signal du compteur de temps 4 pendant la durée fixée au niveau de la temporisation 2.The module 6 which is connected to both the timer 2 and the time counter 4 allows a jamming alarm signal to be sent when it receives a signal from the time counter 4 for the duration set at the timer 2.
De cette manière, dans l'exemple indiqué ci-avant, une alarme sera déclenchée s'il y a eu brouillage moins de 10 minutes après une détection d'intrusion par le détecteur d'infrasons.In this way, in the example indicated above, an alarm will be triggered if there has been interference less than 10 minutes after an intrusion detection by the infrared detector.
Cette alarme est transmise par une liaison filaire 11 à l'entrée temporisée de la centrale d'alarmes 7.This alarm is transmitted by a wired link 11 to the timed input of the alarm center 7.
Le dispositif antibrouillage 10 est conçu de manière à pouvoir compléter des systèmes de surveillance déjà installés.The anti-jamming device 10 is designed so as to be able to supplement already installed surveillance systems.
Certains modèles de centrales d' alarmes ne disposent pas de bornes de connexion filaires, toutes les transmissions d'informations vers la centrale d'alarmes se faisant par voie hertzienne.Some control panel models do not have wired connection terminals, all transmissions of information towards the alarm center being done by hertzian way.
Dans ce cas, tel que représenté sur la figure 2, le dispositif antibrouillage 10 est relié par la liaison filaire 11 à un émetteur radioélectrique 14 réglé sur l'entrée temporisée de la centrale d'alarmes 13, et placé très près de cette dernière. De cette manière, la liaison entre l'émetteur 14 et la centrale d'alarmes 13 ne risque pas d'être perturbée par une tentative de brouillage.In this case, as shown in FIG. 2, the anti-jamming device 10 is connected by the wire link 11 to a radio transmitter 14 set to the timed input of the alarm center 13, and placed very close to the latter. In this way, the connection between the transmitter 14 and the alarm center 13 is not likely to be disturbed by an interference attempt.
Par ailleurs, la centrale d'alarmes 13 est reliée par voie hertzienne à la sirène 16 et à un transmetteur téléphonique 15. Si ces deux éléments sont trop éloignés de la centrale d'alarmes 13 pour être insensibles au brouillage, une liaison filaire pourra être installée entre un récepteur radio placé près de la centrale et ces deux éléments.Furthermore, the alarm center 13 is connected over the air to the siren 16 and to a telephone transmitter 15. If these two elements are too far from the alarm center 13 to be insensitive to interference, a wired connection may be installed between a radio receiver placed near the control panel and these two elements.
Le dispositif 10 antibrouillage peut également comprendre une alimentation sauvegardée 17 pour pouvoir fonctionner même en cas de coupure du secteur. The anti-jamming device 10 can also include a saved power supply 17 so that it can operate even in the event of a power cut.

Claims

REVENDICATIONS
1. Dispositif antibrouillage destiné à équiper un système de surveillance d'intrusions comprenant une pluralité de capteurs reliés par voie hertzienne à un organe central de signalisation d'alarmes, caractérisé en ce que qu'il comprend :1. Anti-jamming device intended to equip an intrusion monitoring system comprising a plurality of sensors connected by radio link to a central alarm signaling member, characterized in that it comprises:
- un détecteur d'émissions de brouillage ( 5 ) sur la fréquence utilisée par les capteurs ( 8 ) pour communiquer avec l'organe central (7),- an interference emission detector (5) on the frequency used by the sensors (8) to communicate with the central body (7),
- un détecteur additionnel ( 1 ) , distinct du système de surveillance, permettant de détecter toute intrusion dans la zone dans laquelle s 'effectuent les transmissions radio-électriques entre les capteurs ( 8 ) er 1 'organe central (7),- an additional detector (1), distinct from the surveillance system, making it possible to detect any intrusion into the area in which the radioelectric transmissions take place between the sensors (8) and the central organ (7),
- un circuit d'alarme ( 6 ) chargé de valider le signal d'alarme émis par le détecteur d'émissions de brouillage (5) vers l'organe central (7), à la suite d'une détection d'un signal de brouillage, si une intrusion esr détectée par le détecteur additionnel ( 1) .- an alarm circuit (6) responsible for validating the alarm signal emitted by the interference emission detector (5) to the central unit (7), following a detection of a signal interference, if an intrusion is detected by the additional detector (1).
2. Dispositif selon la revendication 1, caractérisé en ce que le détecteur additionnel ( 1 ) est un détecτeur d'infrasons.2. Device according to claim 1, characterized in that the additional detector (1) is an infrared detector.
3. Dispositif selon la revendication 1, caractérisé en ce que le détecteur d'émission de brouillage ( 5 ) comprend un récepteur (3) d'ondes radio-électriques calé sur ladite fréquence qui analyse le signal reçu, et un compteur (4) qui reçoit du récepteur (3) une indication de brouillage lorsque le niveau du signal reçu est supérieur à un seuil.3. Device according to claim 1, characterized in that the interference emission detector (5) comprises a receiver (3) of radio waves set on said frequency which analyzes the received signal, and a counter (4) which receives from the receiver (3) an indication of interference when the level of the received signal exceeds a threshold.
4. Dispositif selon la revendication 3, caractérisé en ce que le compteur (4) fournit un signal d'alarme de brouillage au circuit d'alarme (6) lorsque 1'indication de brouillage est présente pendant une durée fixée. 4. Device according to claim 3, characterized in that the counter (4) provides a jamming alarm signal to the alarm circuit (6) when the jamming indication is present for a fixed duration.
5. Dispositif selon la revendication 4, caractérisé en ce que ladite durée fixée et ledit seuil sont réglables.5. Device according to claim 4, characterized in that said fixed duration and said threshold are adjustable.
6. Dispositif selon la revendication 1, caractérisé en ce qu'il comprend une temporisation (2) qui envoie, pendant une certaine période, un signal de validation d'alarme de brouillage au circuit d'alarme (6), à la suite d'une détection d'une intrusion dans ladite zone par le détecteur d'infrasons (1) .6. Device according to claim 1, characterized in that it comprises a time delay (2) which sends, for a certain period, an interference alarm validation signal to the alarm circuit (6), following d 'detection of an intrusion into said zone by the infrasound detector (1).
7. Dispositif selon la revendication 6, caractérisé en ce que la durée de ladite période est réglable.7. Device according to claim 6, characterized in that the duration of said period is adjustable.
8. Dispositif selon la revendication 2, caractérisé en ce que le détecteur d*infrasons (1) comprend un transducteur et un condensateur polarisé transformant en un signal électrique les ondes de pression dues à un déplacement d'air.8. Device according to claim 2, characterized in that the infrasound detector (1) comprises a transducer and a polarized capacitor transforming into an electrical signal the pressure waves due to a displacement of air.
9. Dispositif selon la revendication 1, caractérisé en ce qu'il comprend une alimentation de sauvegarde (17) .9. Device according to claim 1, characterized in that it comprises a backup power supply (17).
10. Dispositif selon la revendication 1, caractérisé en ce qu'il est relié à 1'organe central (7) par une liaison (11) ne risquant pas d'être perturbée par un signal de brouillage.10. Device according to claim 1, characterized in that it is connected to the central member (7) by a link (11) not likely to be disturbed by a jamming signal.
11. Dispositif selon la revendication 1, caractérisé en ce qu*il est relié au système de surveillance par l'intermédiaire d'un câble (11) connecté à un émetteur (14) placé à proximité de l'organe central (13). 11. Device according to claim 1, characterized in that * it is connected to the monitoring system by means of a cable (11) connected to a transmitter (14) placed close to the central member (13).
PCT/FR1994/000076 1993-01-26 1994-01-21 Tamperproof radio anti-jamming device for trespass monitoring systems WO1994017505A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP94905142A EP0681723B1 (en) 1993-01-26 1994-01-21 Tamperproof radio anti-jamming device for trespass monitoring systems
DE69407167T DE69407167T2 (en) 1993-01-26 1994-01-21 INTERFERENCE RADIO DEVICE FOR INTRUSION MONITORING SYSTEMS

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR93/00707 1993-01-26
FR9300707A FR2700873B1 (en) 1993-01-26 1993-01-26 Anti-jamming radio anti-jamming device for intrusion monitoring systems.

Publications (1)

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WO1994017505A1 true WO1994017505A1 (en) 1994-08-04

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FR1994/000076 WO1994017505A1 (en) 1993-01-26 1994-01-21 Tamperproof radio anti-jamming device for trespass monitoring systems

Country Status (5)

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EP (1) EP0681723B1 (en)
CA (1) CA2154755A1 (en)
DE (1) DE69407167T2 (en)
FR (1) FR2700873B1 (en)
WO (1) WO1994017505A1 (en)

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GB2313980A (en) * 1996-06-05 1997-12-10 Yale Security Prod Ltd Anti-jamming radio-type burglar alarm
GB2438009A (en) * 2006-02-24 2007-11-14 Location Company Ltd Vehicle security system

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DE19506385C2 (en) * 1995-02-23 2002-03-07 Peter John Goddard Wireless hazard detection system and notification procedure
IT1309390B1 (en) * 1999-03-02 2002-01-22 Franco Pedrazzi RADIOFREQUENCY RECEIVER BLINDING DETECTOR MODULE OF RADIO WAVE ALARM SYSTEMS.
ES2187293B1 (en) * 2001-10-25 2004-09-01 S.D.P. Sistemas De Proteccion, S.L. SECURITY DEVICE AND INTRUSION ALARM SYSTEM.
US9905120B1 (en) 2016-08-29 2018-02-27 At&T Digital Life, Inc. Alarm initiation when sensor is intentionally jammed
FR3073070B1 (en) * 2017-10-26 2023-05-05 Telecom Design DETECTION AND ALERT DEVICE FOR ALARM SYSTEM AND ALARM SYSTEM COMPRISING IT

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Cited By (3)

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GB2313980A (en) * 1996-06-05 1997-12-10 Yale Security Prod Ltd Anti-jamming radio-type burglar alarm
GB2313980B (en) * 1996-06-05 1999-04-28 Yale Security Prod Ltd Radio-type burglar alarm systems
GB2438009A (en) * 2006-02-24 2007-11-14 Location Company Ltd Vehicle security system

Also Published As

Publication number Publication date
EP0681723A1 (en) 1995-11-15
CA2154755A1 (en) 1994-08-04
DE69407167T2 (en) 1998-07-02
DE69407167D1 (en) 1998-01-15
FR2700873B1 (en) 1995-04-07
FR2700873A1 (en) 1994-07-29
EP0681723B1 (en) 1997-12-03

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