[0001] 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.
[0002] 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.
[0003] 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.
[0004] 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.
[0005] 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.
[0006] In the figure, the system is described with reference to a particular, non limiting,
application of the same on vehicles (5).
[0007] 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.
[0008] 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.
[0009] 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.
[0010] 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.
[0011] 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.
[0012] 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.
[0013] 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.
[0014] 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.
[0015] 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.
[0016] 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.
1. 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.
2. 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.
3. 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.
4. 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.
5. 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.