EP1014325A1

EP1014325A1 - Improvements in anti-intrusion systems against false-alarms

Info

Publication number: EP1014325A1
Application number: EP99121151A
Authority: EP
Inventors: Giuseppe Simonazzi
Original assignee: Meta System SpA
Current assignee: Meta System SpA
Priority date: 1998-12-14
Filing date: 1999-10-22
Publication date: 2000-06-28
Also published as: ITRE980127A1; IT1305345B1

Abstract

An anti-intrusion alarm system is constituted by a plurality of sensors having the same technology, but a covering diagram oriented towards different directions. Such configuration allows alarm signaling in opposite conditions with respect to conventional methods. If two or more sensors signal a breaking with the same intensity, the same is considered as an environment disturbance; if on the contrary, it is sensed by one only sensor, while on the other one or ones it is not signaled or is much less sensed, the real alarm signal is transmitted to the station.

Description

The invention relates to an improvement in anti-intrusion systems against the possibility of false alarms, which is obtained through the elaboration of the signals that come from sensors adopting the same technology.
As is known, in order to prevent the possibility of false signals, double technology sensors are used in the most updated and sophisticated anti-intrusion alarm systems, such as for instance passive IR sensors and microwave sensors, combined with each other. By this concept, in fact, the alarm is transmitted only if the different sensors sense intrusion attempts within a limited time interval and, because of the very fact that the technology employed is different, it is unlike for a simple disturbance to involve all sensors, and the possibility of false alarms due to external factors are minimum. However, it is evident that in the realization of such systems, the combination of the different technologies, the mixed circuit composition, the wiring harnesses of the components having different characteristics and the regulation and/or calibration of the different sensitivities of the sensors, require special attention and contrivances as well as specific experiences and impose longer and more expensive operating times.
Object of the present invention is to obviate the above drawbacks. The invention, as is characterized by the claims, solves the problem by means of an improvement in the anti-intrusion systems by which the possibility that false alarms take place is excluded by utilizing sensors having the same technology, but with covering diagrams oriented towards different directions.
The advantages achieved according to the present invention lie essentially in that the systems are simpler and more homogeneous, the circuits and the related wire harnesses are easier to be realized and assembled, and also the calibration of the sensors of the same type is easy.
The invention is described with more details in the following, according to an embodiment solely given by way of non limiting example, with reference to the attached drawing, wherein: Figure 1 is a plan general layout of a vehicle provided the concerned anti-intrusion system.
In the figure, the system is described with reference to a particular, non limiting, application of the same on vehicles (5).
Its is composed of four sensors, such as for instance ultrasound transducers (1, 2, 3 and 4) applied on a vehicle (5). Each transducer is able to sense anti-intrusion attempts. By said configuration, the alarm signaling is obtained in opposed conditions with respect to conventional methods. If two or more sensors having the same technology signal a breaking with the same intensity, the latter is considered as an environment disturbance; if on the contrary, the movement is sensed by one only sensor, while on the other one or ones it is not signaled or is much less sensed, the real alarm system is transmitted to the station. The elaboration of the signals is carried out carefully by an electronic station, so as to discriminate with certainty the intrusions from the false alarms caused by environment factors.
In substance, the principle on which the intrusion sensing is based is that of the acoustic response, in the case of ultrasound transducers, of the driver's cab. Each sensor emits impulse trains at an ultrasonic frequency of a limited and defined duration.
Between an impulse train and the subsequent one, each sensor acts as a receiver for the ultrasonic waives reflected by the walls and the obstacles that are present in the driver's cab (6) of the vehicle (5). In this way, each transducer can store an "acoustic image" of the environment, meaning that the echoes of the impulse train have different shape and amplitude. The suitable elaboration of the signals allows therefore to sense the aforesaid intrusion attempt.
Depending on the possible environment variations due to heat, cold or humidity or the disturbances coming from the outside of the vehicle (5), such as those produced by rain, wind, hail or various noises, the system might result to be easily subject to false alarms, unless the sensitivity to variations of the responses of the sensors is drastically reduced.
Instead, the method subject matter of the present invention consists in the real time examination of the responses obtained from all sensors; the simultaneous elaboration of such signals allows to easily discriminate an intrusion attempt from a false alarm. An environment variation, in fact, is sensed in a similar manner by all the sensors of the system; in the case under examination, by four transducers applied in the inside of the vehicle (5). The same holds good for the disturbances coming from the outside.
If, on the contrary, the disturbance is caused by a real breaking attempt, for instance originating by the shattering of the glass or the forcing of the left front door lock, the sensor (1) directly involved receives as an echo of the transmitted signal an "acoustic image" very different from the previously stored one, in rest condition; sensors (2) and (3) will be, instead, little affected by the same disturbance, while sensor (4), even though involved, will sense much less the disturbance.
Vice-versa, in case of rain, all sensors result to be equally "disturbed" by the corresponding noise produced by water hitting the metal body of the vehicle (5), and the variations in the "acoustic image" are similar and comparable.
By means of an adequate elaboration of the signals received by the electronic station and coming from all sensors, it is possible to discriminate the breaking attempts from false alarms.
In relation with what has been described for the particular application on vehicles, it is obvious that the same working principle can be easily adopted, in the same way and for the same purposes, utilizing two or more sensors employing a technology equal to the one previously described, or also with sensors using different technologies. In the same way, two or more sensors employing any known suitable technology may be adopted either for the protection of moving means, such as motor-cars and/or the like, and for the protection of fixed means, such as for instance houses, rooms and the like.
Even though the invention has been described and illustrated according to an embodiment solely given by way of non limiting example, it will be obvious to those skilled in the art that many modifications in the forms, details, orientations, combinations and assemblies may be introduced without for this falling outside its scope and aim.

Claims

Improvements in anti-intrusion systems against the possibility of false alarms, characterized in that it is obtained through the elaboration of the signals coming from equally calibrated sensors, that adopt the same technology but are arranged according to covering diagrams oriented towards different directions.
The improvements in anti-intrusion systems against the possibility of false alarms according to claim 1, characterized in that the possibility that false alarms take place is excluded by the adoption of sensors having the same technology but covering diagrams oriented towards different directions, and in that alarms signals are obtained in opposite conditions with respect to the conventional methods.
The improvements in anti-intrusion systems against the possibility of false alarms according to claims 1 and 2, characterized in that signals having the same intensity, sensed by two or more sensors, correspond to an environment disturbance.
The improvements in anti-intrusion systems against the possibility of false alarms according to claims 1-3, characterized in that to a real breaking a signal corresponds that is sensed by a sensor with an intensity different from the signals sensed by other sensors: said signal is not sensed or is much less sensed by the other one or ones sensors of the system.
The improvements in anti-intrusion systems against the possibility of false alarms according to claims 1-4, characterized in that the train of sensors which adopt the same technology utilizable for the constitution of anti-intrusion systems subject matter of the invention are of the ultrasound, passive IR, microwave type, or any other suitable type.