EP0312431B1 - Remote goods and/or persons supervising method - Google Patents

Description

The present invention relates to a method of remote monitoring in particular of goods and / or people for the remote detection of events of all kinds possibly requiring rapid intervention at the places where the events took place.

There are known methods of remote monitoring ensuring the protection of persons against attacks and of property against burglaries, of the type consisting in transmitting alarm signals coming from a certain number of transmitting devices located in geographically distinct places and received at a central commum station such as the nearest police station to the incident site (s). See for example GB-A-2.186404.

However, given the presence of a large number of transmitting devices located respectively in geographically different places monitored by the common central station, several alarm signals originating from some of these transmitting devices can be received simultaneously at the central station, causing thus a problem of collision of these signals at the central station.

The object of the present invention is to eliminate the above drawback by proposing a method of remote monitoring according to claim 1.

Furthermore, in order to provide the remote monitoring method of the invention with a sufficient degree of security so that an unauthorized person cannot have access to the coded alarm information and completely jam it, each alarm information from each transmitting device is subdivided into several pieces of information sent to the central station respectively on different channels or different frequencies, chosen according to a randomly established composition rule.

According to a characteristic of the invention, the method consists, as soon as a significant event of an alarm is detected at at least one of the transmitting devices, to transmit from the transmitting device to the central station a radio signal carrying at least minus coded information relating to the above-mentioned composition rule of the transmission channels or frequencies to and memorize it at the central station.

According to another characteristic of the invention, the aforementioned radio signal also carries coded information relating to the type of coding of the channels or frequencies and stored in the central station, said signal being transmitted on a channel or a frequency also chosen randomly.

Still according to another characteristic of the invention, each transmitter device is associated with a receiver device and the central station further comprises a transmitter device transmitting to the transmitter-receiver devices an acknowledgment signal of reception of the signal carrying at least 1 coded information relating to the aforementioned rule and setting of the receiving device of the central station on the chosen channel or transmission frequency, the acknowledgment and setting signal containing an identification code of the channel or the frequency used and a code relating to the quality of reception observed at the central station.

• ― la figure 1 représente un dispositif de télésurveillance comprenant un dispositif émetteur de signaux d'alarme vers un dispositif récepteur d'un poste central; et
• ― la figure 2 représente un organigramme de fonctionnement du dispositif émetteur.

The invention will be better understood, and other objects, characteristics, details and advantages thereof will appear more clearly during the explanatory description which follows, made with reference to the appended schematic drawings given solely by way of example illustrating a embodiment of the invention, and in which:

• - Figure 1 shows a remote monitoring device comprising a device transmitting alarm signals to a receiving device from a central station; and
• - Figure 2 shows a flowchart of operation of the transmitter device.

The invention will be described with reference to a device for remote monitoring of property against burglaries, but it is understood that the invention can be applied to another different field as will be explained later.

The remote monitoring device shown in Figure 1 comprises a transmitter device 1 arranged to transmit a radio alarm signal to the receiving device of the central station.

The remote monitoring device in fact comprises a plurality of transmitter devices 1 located in geographically distinct places to be monitored by the common central station such as a police station.

The transmitting device 1 comprises several inputs 10, for example 8 in number respectively connected to sensors triggering the emission of the radio alarm signal in the event of, for example, a break-in, a processing device 11, preferably with microprocessor, signals received at the inputs 10, a modulation device 12 intended to modulate one or more carrier frequencies by the low frequency alarm information signals coming from the processing device 11 and a filtering device 13 connected at the output of the modulation device 12 The analog signals applied to the inputs 10 are digitally converted by an analog-digital conversion device 14 connected to the processing device 11.

In the standby state of the transmitting device 1, the 8 inputs 10 are at a low level (OV) and the detection of a break-in by one of the sensors results in a high level at the corresponding input terminal. The digital signal from the analog-digital conversion device 14 is transmitted to the processing device 11 which is adapted to produce the alarm information composed for example of eight binary signals, four of them relating to the identification number of the person owning the transmitting device 1, two others at the geographical area where the transmitting device is located and the last two at the identification number of the sensor requested.

FIG. 2 represents the general flow diagram of the operating program of the processing device 11 for the emission of radio alarm signals and which, since it is insufficiently self-explanatory, will be described quickly.

When at least one of the sensors associated with the sending device 1 detects a particular event such as a break-in, the device 1 is powered up and emits a first radio alarm signal in a maximum time interval authorized by the PTT fixed at 20 seconds. This signal consists of a carrier of a predetermined frequency modulated by the coded information which advantageously comprises three successive identical codes, each relating to the aforementioned parameters coded in the form of the eight binary signs of four bits. This first signal will be transmitted on a channel defined by the filtering device 13. At the end of the maximum time interval, the modulation device 12 is put out of service and a time delay of five minutes (radio silence) imposed by the PTT is triggered. For safety reasons, two other radio alarm signals identical to the first signal will be sent to the central station under the same conditions as above.

According to the invention, as soon as the timer is triggered at the end of the time interval during which the first radio alarm signal has been emitted, the processing device 11 is adapted to randomly calculate a time value in relation to the parameters specific to said transmitting devices 1 which are the geographical area where the transmitting device is located, the number identifying the person owning the device and / or the identification number of the sensor requested. Of course, such a time value can be calculated from other parameters such as for example the date and time of detection of a break-in. From this calculated time value, the processing device 11 modifies the value of the time delay, for example by adding or subtracting from it the calculated time value. This new time value thus obtained will be the instant of transmission of the second radio alarm signal. Likewise, the instant of emission of the third radio alarm signal will be determined randomly as a function of a new value of the calculated time modifying the value of the time delay.

Insofar as the radio alarm signals of each transmitting device 1 are transmitted respectively at instants determined randomly as a function of parameters specific to the transmitting devices, the risks of simultaneous reception by the central station of at least two alarm signals respectively from two different transmitting devices are considerably reduced.

Each radio alarm signal from a transmitting device is received at the receiving device of the central station, filtered and demodulated in the filtering and demodulating device 20 in order to transmit a low frequency analog signal of the alarm information. to an analog-digital transcoding device 21, the digital outputs of which are connected to a processing device 22 preferably with a microprocessor. The processing device 22 is connected to a device 23 for displaying information relating to the geographical area where the alarm was triggered, to the identification of the person owning the transmitting device and / or to the identification of the sensor requested, this information can also be printed on a printer 24 connected to the processing device 22. This information can also be stored in a memory device 25 and subsequently displayed on the display device 23.

Furthermore, in order to solve the interference problems mentioned above, each coded alarm information item of the sending device 1 is subdivided by the processing device 11 into several parts or sections of information sent to the central station respectively on different sending channels. or different transmission carrier frequencies, chosen according to a randomly established composition rule specific to the transmitter device 1. By way of example, the processing device 11 is adapted to split the coded alarm information into four parts of information transmitted respectively on four channels n1-4 or frequencies f1-f4 chosen at random, the composition rule can be based for example on the date and time of detection of the event such as a break-in, by one of the sensors associated with the emitting device 1. The processing device 11 can by example choose the first two binary signals relating to the identification of the person owning the transmitter device 1 so that they are transmitted on a first channel n1 or frequency f1, the other two binary signals relating to this identification to transmit them on the transmission channel n4 or the transmission frequency f4, the two binary signals relating to the geographical area where the transmitting device 1 is located to transmit them on the transmission channel n3 or the transmission frequency f3 and the last two binary signals relating to the identification of the sensor requested to transmit them on the transmission channel n2 or the transmission frequency f2. It should be noted that the processing device 11 is connected to the modulation device 12 for choosing according to the randomly established rule the carrier frequencies for transmitting the alarm information and to the filtering device 13 for choosing according to this same rule the alarm information transmission channels. After reception and demodulation of the signals received at the reception device 20 of the central station 2, the alarm information is transmitted to the processing device 22 by the transcoding device 21, the processing device 22 decoding and reconstructing the information of alarm which is displayed on the display device 23 and / or printed on the printer 24 and / or stored in the memory device 25. It should be noted that the eight binary signals constituting the alarm information can be chosen by the processing device 11 to the sending device 1 in any order, different from that mentioned above. The processing device 22 is adapted to reconstruct the alarm information even if at least one of the binary signals is missing as could be the case during jamming, the other three pieces of information received at the central station being sufficient to allow such a reconstruction.

Of course, it is necessary to transmit to the receiving device of the central station the composition rule allowing it to lock onto each channel or transmission frequency chosen randomly to the sending device 1.

This can be achieved during a so-called learning phase consisting in transmitting on a randomly chosen channel to the transmitter device 1 an FM carrier modulated closely by a signal comprising coded information indicating the composition rule for finding the channels n1-n4, the channel used randomly can be one of channels n1-n4 or a different channel, the main thing being that the emission channel of the FM carrier is in a reception bandwidth of the receiving device 2 sufficiently wide to also receive signals transmitted later on channels n1-n4. The information signal modulating the FM carrier may also include a code relating to the type or rule of coding the channels n1-n4, for example a cyclic coding. The receiving device 2, which is in broadband reception, detects the emission of the closely modulated FM carrier signal and an electronic device forming, for example, part of the device 20 decreases the bandwidth of a broadband reception filter of the device 20 until precisely detecting the aforementioned channel used. The FM carrier signal is then demodulated so as to transmit to the processing device 2 the information relating to the composition rule of the transmission channels n1-n4 and to the coding rule for these channels, this information being stored in the memory device. 25.

When the transmission has ended, the sending device 1 and the receiving device 2 of the central station are prepared to communicate on the four different channels or four different frequencies, the sending of the alarm signals from the sending device 1 being carried out as described above. the composition rule and the processing device 22 of the receiving device 2 is adapted to calibrate the filtering device 20 on each channel or transmission frequency chosen randomly from the coded information relating to the composition rule to find the channels n1-n4 or the frequencies f1-f2.

In addition, each sending device 1 can be associated with a receiving device and the central station can also include a sending device. This structure makes it possible to ensure the smooth flow of information exchanges between the sending device 1 and the receiving device 2 of the central station during the learning phase. In fact, after having precisely detected the channel or the frequency used to transmit the closely modulated FM carrier mentioned above, the transceiver device 2 of the central station switches to transmission mode to transmit from the processing device 22, using the device receiver associated with the transmitting device 1 a signal of acknowledgment of reception of the FM carrier signal and setting of the receiving device 2 on the channel or the frequency used once the transmission of the FM carrier signal from the transmitting device. The acknowledgment and calibration signal will contain in coded form the identification number of the channel used as well as the quality of reception noted. The transceiver device 2 will then return to reception mode. After receiving the acknowledgment and timing signal from the central station, the device transceiver 1, which has returned to transmission mode, retransmits an FM carrier signal containing in coded form the acknowledgment and calibration signal, the composition rule for finding transmission channels n1 to n4 or frequencies f1 at f4, the coding rule used for these channels or frequencies and, where appropriate, an emergency code in the event that an event such as a break-in is detected by one of the sensors of the transmitting device 1 during this phase learning. This second FM carrier signal modulated by this coded information is received by the transceiver device 2 which demodulates it in order to extract the information which is compared with that which had been previously transmitted, so as to ascertain its identity. The significant emergency code for a break-in is stored in the memory device 25 for confirmation during the communication between the sending device 1 and the receiving device 2 on the four channels or four transmission frequencies chosen at random.

Once this learning or preparation phase is complete, the emitting device 1 is ready to emit alarm signals on the randomly chosen channels or frequencies upon detection of a significant alarm event by one of the associated sensors in the manner already explained previously.

It should be noted that the preparation phase 2 is initialized as soon as a significant alarm event is detected by one of the sensors associated with the transmitter device 1 with the condition that the time taken to transmit the modulated FM carrier signal including in particular the coded information representative of the composition rule and possibly re-emitting in the case of communication bi-directional between the receiving device associated with the sending device 1 and the central station is within the maximum authorized time interval.

When the transmission of the three alarm signals is finished, the processing device 22 is adapted to erase the information relating to the composition rule and to the type of coding of the transmission channels or frequencies stored in the memory device 25.

The present invention can also be applied to the medical surveillance of persons, to the transmission of personal, industrial or military information.

Claims (9)

1. A Tele-surveillance system, in particular of property and/or people for detection at distance, with a common central unit of alarm data which are transmitted as radio-electric signals from at least two transmitters, with their relevant detectors placed in different geographical positions, and the distinguishing features of which are:

a) the transmission from each transmitter (1) of initial alarm data, after one of the detectors linked to the transmitter has picked up a significant alarm signal.

b) the setting-off of the alarm at the end of the transmission of this initial alarm data with a fixed value delayed action.

c) the random calculation, from the outset of the delayed action, of a time value, in relation to the parameters, for example, relative to each transmitter, such as the geographical position of the transmitter, the identity number of the transmitter owner, and/or the identification number of the detector involved;

d) the modification of the value of the delayed action in accordance with the time value, randomly calculated to add or substract the calculated time value to or from the delayed action value.

e) the transmission of at least one other alarm data at the end of the delayed action, corresponding to the said modified value of the delayed action.

2. A system in accordance with statement 1. the distinguishing features being the modification of the delayed action time value, which involves the addition to or substraction from the delayed action of the decided value, of the said randomly calculated time value.

3. A system in accordance with one of the former statements, the distinguishing features being that each alarm codes, and transmits the alarm data a certain number of times ― for example ― 3.

4. A system in accordance with one of the former statements, the distinguishing features being that, in addition each alarm data is subdivising into several data sections, and the data sections are transmitted to the central unit (2) respectively, on different transmission carrier channels or frequencies, chosen in accordance with a randomly established compound rule.

5. A system in accordance with statement 4., the distinguishing features being the transmission, as soon as a significant alarm incident is detected, at at least one of the transmitters (1) from the transmitter (1) to the central unit (2) of a radio-electrical signal, carrier of at least one coded data, relative to the compound rule previously mentioned, tranmission channels and frequencies and the memorisation of that rule in the central unit (2).

6. A system in accordance with statement 5., the distinguishing features being the radio-electical signal previously mentioned is also the carrier of coded data relative to the type of channel or frequency coding and memorised in the central unit (2), the said radio-electrical signal being transmitted on a channel or frequency chosen randomly.

7. A system in accordance with statements 5 or 6 the distinguishing features being that each transmitter (1) is linked to a receiver, and that the central unit also contains a transmitter, transmitting a reception acknowledgement signal to the transmitter/receiver from the receiver of the central unit (2), on a chosen carrier channel or frequency signal transmission of at least the coded data, relative to the above mentioned rule, and to adjust the receiver of the central unit (2) of the said signal, the reception acknowledgement signal, and an adjustment containing a channel or frequency identification code used and a code relating to the reception quality recorded at the central unit (2).

8. A system in accordance with statement 7-, the distinguishing features being that the transmitter (1) retransmits a radio-electrical signal to the central unit (2) on the channel or frequency chosen, and mentioned above, and the carrier of the relative code respectively of the compound rule and the type of channel coding or frequency transmission and possibly an emergency alarm code.

9. A system in accordance with one of previous statements, the distinguishing features being the deletion of the data relative to the compound rule and the type of coding and memorised channels in the central unit (2), once the transmission of the radio-electric alarm signal has been received.

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