WO2007011258A1

WO2007011258A1 - Method for radio communication between guarded objects and a centralised security station

Info

Publication number: WO2007011258A1
Application number: PCT/RU2006/000290
Authority: WO
Inventors: Vladimir Petrovich Gribok; Sergey Alexandrovich Kosarev; Yuriy Vitalievich Raygorodsky; Valeriy Vladimirovich Slastin; Alexey Ivanovich Faleev; Alexandr Yurievich Sheptovetsky
Original assignee: Obschestvo S Ogranichennoj Otvetstvennostju 'altonika'
Priority date: 2005-07-19
Filing date: 2006-06-02
Publication date: 2007-01-25
Also published as: RU2278415C1

Abstract

The invention relates to alarm-monitoring frequency-hopping signalling. The inventive method consists in forming acknowledge, control or alarm messages in a guarded object and in transmitting said messages to the centralised security station, wherein, during the message formation, a transition from a logical zero to a logical unit is carried out by means of a carrier frequency shift, in determining, while the message transmission, an expected time interval between the transmissions of the actual and next guarded object messages and the next message carrier frequency, upon the termination of the message transmission, in waiting the reception of a control signal from the centralised security station during a defined time interval. In the centralised security station, the inventive method consists in carrying out a wideband reception of signals when the current time approaches the recorded time of the subsequent message delivery, in transiting the output frequency band in the lower frequency range, in carrying out the analog-to-digital conversion and in selecting the frequency ranges which are close to the transmission frequency of the zero and unit symbols in the expected message, in determining the bit change times in the message and the time delay by successively shifting a digital filtration time and in decrypting the message. The control signal is transmitted to the guarded object through the same frequencies. Said invention makes it possible to extend the signalling system service area.

Description

The method of radio communication between protected objects and a central security point

The invention relates to methods for transmitting control and alarm signals using radio communication systems with frequency hopping. Such methods can be used in equipment that establishes a radio link between a central security point (CC) and guarded objects, which can be both vehicles and real estate.

The radio communication systems used in this equipment are used to transmit command messages from the central monitoring station to any selected protected object and any acknowledged messages (confirming the receipt of the command message), control messages or alarm messages from any protected object to the central monitoring station. The most significant is the transmission of alarm messages to the central monitoring station, since the generation and transmission of alarm messages occurs in case of an emergency at the corresponding guarded object, for example, in case of fire or if unauthorized persons are exposed to the guarded object. Such unauthorized persons may be intruders who penetrated the protected object with the purpose of robbery.

Two main types of equipment for a radio communication system are known (from the point of view of organizing the transmission of any messages from a guarded object to a central monitoring station).

The first type includes such equipment of the radio communication system in which the moment of formation and transmission of the next message is not known at the guarded object and, as a rule, in the central monitoring station. A certain message is sent from the protected object only after

SUBSTITUTE SHEET (RULE 26) the occurrence of an event causing a subsequent transfer. For example, as soon as a fire alarm sensor is triggered, an alarm message about a fire is immediately generated and transmitted to the PCO. Such equipment of a radio communication system is described, for example, in patents DE JY ° 4337211, G 08 V 25/10, G 08 V 29/00, G 08 C 15/00, H 04 V 7/24; EP Jfe0651361, G 08 V 25/10; RU Ж2244959, G 08 В 25/10, G 08 В 29/16, В 60 R 25/10. The advantages of such equipment of the radio communication system are the high speed of transmission of alarm messages and low load of the radio communication channel, since the transmission of a message occurs only when the corresponding event occurs, and such events are quite rare. However, this type of equipment of the radio communication system has certain disadvantages. If, during the intrusion of intruders, they were able to immediately (that is, before transmitting the alarm message) disable the transmitting device of the protected object, then no further obstacles would arise for their further actions.

In the second type of equipment of the radio communication system at each guarded object, it is possible to determine in advance the moment of formation and transmission of the next message. And at the central monitoring station, with a certain degree of certainty, it is possible to predict the moments of receipt of the next messages from each of the protected objects. The number of messages transmitted to the central monitoring station from each guarded facility for such equipment of the radio communication system for each hour is very noticeable (usually from 15 to 30). Such equipment of a radio communication system is described, for example, in patents US N26188715, H 04 L 27/26; US M> 6,700,920; H 04 V 01/713; US JV <> 6870875, H 04 V 01/69. The equipment of this type of radio communication system has a number of disadvantages. In particular, the speed of transmitting alarm notifications is very low (the time interval from the operation of the fire detector to

SUBSTITUTE SHEET (RULE 26) the corresponding alarm message can be several minutes), the download of the radio channel is quite high (with 100 guarded objects about 2,000 messages per hour arrive at the central monitoring station). However, attackers face a much more difficult task when they invade a protected object. In the PCO, the termination of the transmission of messages from any protected object is considered as an alarm message about the intrusion of intruders. Therefore, it is not enough for an attacker to simply suppress the transmission of an alarm message; it is also necessary to form some artificial messages on the radio air, which in the central monitoring station should be taken for messages from this protected object, indicating its normal operation.

An object of the present invention relates specifically to the latter second type of apparatus of a radio communication system. And with this equipment, the transmission of messages must be carried out taking into account all the strict restrictions on the power and on the carrier frequency of the radio signal introduced on the territory of a state.

So, for example, if the guarded object is a vehicle, then in Russia restrictions are set on the frequency and power of radio signals in the alarm equipment:

- carrier frequency (433.92 MHz ± 0.2%);

- maximum radiation power of 25 mW.

However, to ensure the competitiveness of the sold wireless alarm equipment, the manufacturer requires that the user of the alarm equipment do not issue special permits for the purchase and use of this equipment. Issuing permissions creates inconvenience for the user, which leads to the fact that the user

SUBSTITUTE SHEET (RULE 26) refuses to purchase similar equipment from this manufacturer and is looking for another manufacturer.

For alarm equipment that can be used, for example, in Russia without official authorization, the nominal radio frequencies and power are limited to 433.92 MHz ± 0.2% and 5 mW, respectively (when installed on vehicles) and 10 mW (for other protected sites).

With such small signal powers, the distance of the protected objects from the central monitoring station should be several hundred meters. This is not enough to build effective wireless alarm equipment.

The traditional way to increase the distance of protected objects from the central monitoring station is to use the relay of signals of protected objects. However, the construction of a network of repeaters causes additional costs for construction work and, in addition, requires the permission of the state radio frequency services and permissions from the owners of the structures on which the repeaters are installed. One of the promising methods providing the possibility of transmitting messages from protected objects to the central monitoring station without using an extensive network of repeaters is the use of “jumping” frequencies in transmitted messages (Freepeps horpip). Based on the application of this method, centralized security systems are described in the aforementioned patent patents: US Nsb 188715, H 04 L 27/26; US JCO 6700920, H 04 V 01/713; US DO.6870875, H 04 B 01/69. It should be noted that the use of "jumping" frequencies makes it difficult for an attacker to form artificial messages on the air. In order for the artificial communication in the PCO to be

SUBSTITUTE SHEET (RULE 26) received as a message from this protected object, indicating its normal operation, this artificial message should not only begin at the appropriate time, but should also be transmitted at the appropriate carrier frequency. In addition, the use of “jumping” frequencies significantly reduces the likelihood that a pair of messages will be lost due to the coincidence of the transmission time intervals: for the loss of a pair of messages, the proximity of their carrier frequencies is also needed. However, if you do not control the choice of transmission start times and carrier frequencies, then loss of message pairs cannot be avoided. Let's say that messages from a hundred of protected objects come to the PCO. At the same time, for each protected object, the time interval from the beginning of the transmission of any message to the beginning of the transmission of the next message is set within two to four minutes (with a hundred equally probable choices). Suppose further that the number of equally probable carrier frequency selection options for each message is one thousand. Then, every hour in the central monitoring station, two to three pairs of messages generated by different protected objects will be lost.

In one of the known technical solutions (in the patent US JN ° 6870875, H 04 В 01/69), measures were taken to select the moments of the beginning of the transmission of messages and carrier frequencies in order to avoid loss of message pairs due to their overlap (in time and carrier frequency). Implemented in this technical solution, the method is the closest to the claimed. The technical solution for this patent is selected as a prototype of the proposed method.

The implementation of this method under the conditions of the restrictions in the range of radio frequencies and capacities in the states does not allow to increase the range of the equipment to more than (0.5-1.0) km. Of this

SUBSTITUTE SHEET (RULE 26) not enough for products intended for free market sale.

The present invention is aimed at improving the prototype, taking into account current restrictions on the range of radio frequencies and powers.

The subject of this invention is a radio communication method between guarded objects and a central monitoring station, in which the central monitoring station identifies the need for a corresponding control signal for each protected object, generates a binary code for this control signal and transmits it over the air as part of a command message received at the corresponding protected object, in each of the protected objects they form in binary code and transmit acknowledgment, control or alarm messages to the PCO via radio, moreover, the acknowledgment message A message is generated after receiving a command message from the PCA, an alarm message - after an alarm event is detected at the guarded object, and a control message - if there are no conditions for the generation of an acknowledgment and alarm message, the alarm event is detected in the PCC, which caused the alarm message to be generated, and make a decision adequate to the disturbing event that occurred, when transmitting from each protected object any message - acknowledging, monitoring or alarming - determined dissolved expected T the time interval between the moments of the start of transmission of this and the next message of the protected object and the carrier frequency F of the next message, wherein to select the expected T time interval using three matched to all protected objects of the indicator: the minimum allowable time interval Tmin ₅ maximum time interval T _MAX ^AND step Δ _t

SUBSTITUTE SHEET (RULE 26) the choice of the time interval, and to select the carrier frequency F of the next message also use three indicators that are the same for all protected objects: the minimum allowable frequency F _M in, the maximum allowable frequency F _MAX AND the step Δ _{F of} the frequency grid, the determination of the expected time interval T is carried out by selecting the pre-established for each protected facility pseudorandom algorithm with equal probability of choosing the number of K _t in the range 0 <K _T <(T _MAKC -T _MИH ) / Δ _T and using the relation T = T _M in + bC _t Δ _t , and determining the carrier part The following message F is carried out by selecting, according to a similar pre-established algorithm for each protected object, a pseudo-random equiprobable choice of the number K _F within 0 <K _F <(F _MAKC -F _MИH ) / Δ _F and using the relation F = F _MИH + K _F Δ _F , - at the same time, each of the pseudorandom equiprobable algorithms pre-installed for the protected objects is stored in the PCO and these algorithms are used to determine and subsequently memorize the time moments of receipt of the next messages from each of the protected during the formation of messages, they carry out the transition from a logical zero to a logical unit by shifting the carrier frequency F by an integer number K of steps Δ _{F of} the frequency grid that exceeds unity and constant for all protected objects, as the current time approaches a memorized time the arrival of the next message from one of the protected objects carries out broadband signal reception, transfers the input frequency band to the region of lower frequencies, performs analog-to-digital conversion azovanie and digital filtering techniques, taking into account the transfer of produced input baseband recovered frequency ranges close to those frequencies at which the expected

SUBSTITUTE SHEET (RULE 26) symbols of logical zero and logical units must be transmitted, and if there is no reception of the expected message in the selected frequency areas, they shall take measures adequate to the measures taken when an alarm message is received from the corresponding protected object, if there is a message received by successively shifting the digital filtering time interval by a step, shorter than the transmission time interval of one bit in the message, determine the moments of change in the bits in the message and the shift in time of the start of the message, call Considered by the mismatch of the reference frequency of the generators in the monitoring station and the protected object, they will decrypt the received message and take actions adequate to its content and taking into account the conditions that occur in the central monitoring station, check whether these actions require a control signal to be sent to the protected object, and if there is such a requirement, form a command message containing the desired control signal, and transmit it at frequencies of logical zero and logical units in the received PCO message with amendments taking into account the set when In the case of the message, the reference frequency of the generators in the monitoring station and the protected object does not match, and at the protected object, after the end of each message transmission, a command is received from the central monitoring station at the same frequencies at which the last message was transmitted from this protected object.

Particular features of the invention are as follows. In the PCO, when determining the time of arrival of the next message from the protected object, the expected time interval for receiving the next message is compared with the previously expected time intervals for the receipt of messages from other protected objects, and the presence of the overlap of these intervals on the expected time

SUBSTITUTE SHEET (RULE 26) the reception interval for the next message, taking into account the duration of the additional time interval for the submission of the command message, if such an overlap is detected, the presence of the proximity of the carrier frequencies is checked and, with the proximity of the carrier frequencies established, a change command is generated for the protected object under consideration for the formation and / or carrier frequency of the next message, and then stored in PCO and guarded object adjusted parameters.

Using the commands generated in the PCA, the time interval T between the moments when the transmission of this and the next message starts from the corresponding protected object is increased to the maximum allowable value T _MAX .

Digital filtering of messages in the central monitoring station is carried out using the fast Fourier transform. When using the fast Fourier transform, an allowable frequency overlap is established in adjacent spectral regions, at least a step Δp of the frequency grid.

In the structure of each message, a synchronization marker, an information block made using error-correcting coding, and a checksum are distinguished.

The objective of the invention is the creation of a technology that provides an increase in the range of the known alarm equipment used in the protection of vehicles and real estate, taking into account the actual restrictions on the nominal values of the used radio frequencies and radiation powers of the transmitters.

The technical result of the invention is to create a fairly simple in technical implementation and not having restrictions

SUBSTITUTE SHEET (RULE 26) for free market sale of system equipment intended for use in alarm systems.

The invention is illustrated using the drawings shown in Fig.l - Fig.Z. Figure l explains the concept of the proposed method of radio communication between protected objects and PTOs.

At ^'2 is a block diagram of an exemplary technical realization of the apparatus of the protected object.

On Fig.3 shows a structural diagram of an example of a technical implementation of the equipment PTsO.

In figure 2 and fig.Z the following notation is used: 1 - sensor; 2 - object control unit; 3 - object receiver; 4 - node pseudo-random selection; 5 - object frequency register; 6 - object time register; 7 - object time counter; 8 is a coincidence diagram; 9 - object driver of the message; 10 auxiliary time register; 11 - current time counter; 12 is a first comparison diagram; 13 is a block of pseudo-random selection nodes; 14 - auxiliary address register; 15 - central frequency register; 16 - central time register; 17 - heterodyne receiver; 18 - analog-to-digital Converter; 19 is a block of digital filters; 20 - auxiliary frequency register; 21 - a crucial unit; 22 - central control unit; 23 - buffer memory; 24 is a second comparison diagram; 25 - shaper command message.

The equipment of the guarded facility is installed on the corresponding guarded property or in a vehicle. In this case, the structure of an example of technical implementation of the equipment of the protected object (figure 2) includes sensors 1, the outputs of which are connected to the object control unit 2. The corresponding outputs of the object control unit 2 are connected

SUBSTITUTE SHEET (RULE 26) to the input of the pseudo-random selection node 4, to the first input of the object time register 6, to the first and second inputs of the object time counter 7 and to the first input of the object shaper 9 messages configured to transmit the corresponding messages over the air to the central monitoring station. The outputs of the object register 6 and the object counter 7 are connected to the corresponding inputs of the matching circuit 8, the output of which is connected to the first input of the object control unit 2 and to the second input of the object driver 9 messages. The third input of the object driver 9 messages is connected to the output of the object register 5 frequency and is connected to the input of the object receiver 3, configured to receive the corresponding command messages from the central monitoring station via radio. The output of the object receiver 3 is connected to the second input of the object block 2 of the control, and the outputs of the node 4 pseudo-random selection are connected, respectively, to the second input of the object register 6 time and to the input of the object register 5 frequency.

The equipment of the central monitoring station is installed in general for all protected objects of the central monitoring station. At the same time, the heterodyne receiver 17 made with the possibility of receiving messages from protected objects is included in the example of technical implementation of the PCO equipment (FIG. 3). The output of the heterodyne receiver 17 through an analog-to-digital converter 18 is connected to the first input of the digital filter block 19. The second input of the digital filter block 19 is connected to the first input of the block 13 of the pseudo-random selection nodes and to the output of the first comparison circuit 12. The first input of the first comparison circuit is connected to the output of the current time counter 11, and the second input is connected to the output of the auxiliary time register 10 and to the first input of the central control unit 22, the second input of which is connected to the first output

SUBSTITUTE SHEET (RULE 26) block 19 digital filters. The second output of the digital filter unit 19 through the decision unit 21 is connected to the third input of the Central control unit 22. In this case, the second input of the block 13 of pseudo-random selection nodes is connected to the output of the auxiliary address register 14. The first output of the block 13 of pseudo-random selection nodes is connected through the central frequency register 15 to the fourth input of the central control unit 22. The second output of the block 13 of pseudo-random selection nodes is connected to the first input of the central time register 16, the output of which is connected to the fifth input of the central control unit 22, the sixth input of which is connected to the output of the second comparison circuit 24. The first input of the second comparison circuit 24 is connected to the first output of the buffer memory 23, the first input of which is connected to the second input of the second comparison circuit 24 and to the first output of the central control unit 22. The second output of the central control unit 22 is connected to the input of the command message generator 25 configured to transmit command messages for the respective protected objects over the air. The seventh input of the central control unit 22 is connected to the second output of the buffer memory 23, the second input of which is connected to the third output of the central control unit 22, the fourth output of which is connected to the second input of the central time register 16. The third, fourth and fifth outputs of the buffer memory 23 are connected to the inputs, respectively, of the auxiliary time register 10, the auxiliary address register 14 and the auxiliary frequency register 20. The output of the auxiliary frequency register 20 is connected to the third input of the digital filter unit 19.

Sensors 1 are technical means of fire and security alarm systems designed to detect a fire at a guarded object or to detect penetration (attempts

SUBSTITUTE SHEET (RULE 26) penetration) of unauthorized persons to the protected facility, as well as to identify the fact of exposure to the protected facility that exceeds the normalized level. That is, the sensors 1 detect alarm events at the guarded object. Upon detection of alarm events, the sensors 1 generate the corresponding alarm notifications. In addition, the sensors 1 can also generate control and diagnostic alerts. The types and main characteristics of technical means of fire and security alarms are widely known in the scientific and technical literature (for example, "Directory of engineering and technical workers and electricians of technical means of security and fire alarms", Moscow, Ministry of Internal Affairs, GUVO, 1997).

The object control unit 2, the decision unit 21, the central control unit 22 and the second comparison circuit 24 can be performed, for example, according to the programmable controller circuits. As an analog-to-digital Converter 18 can be used with standard commercially available chips.

Block 19 of digital filters can be made on the basis of digital filtering nodes of an integrating type using the fast Fourier transform method. The structure of the equipment of each guarded object includes a special pseudo-random selection node 4 designed specifically for this guarded object. It allows pseudo-random selection of the carrier frequency of the next message and the time interval between sending this message and sending the previous message. For simplicity of presentation, we can assume that the node 4 of the pseudo-random choice is a constant non-volatile memory (although in practice the choice of hardware implementation of the node 4 of the pseudo-random choice can be extremely wide). For this embodiment, the node 4 pseudo-random selection block 13 nodes

SUBSTITUTE SHEET (RULE 26) a pseudo-random selection is a set of storage devices, the contents of each of which completely coincides with the contents of the node 4 of the pseudo-random selection (which is part of the corresponding protected object). Block 13 nodes of the pseudo-random selection is made with the possibility of selecting a specific storage device according to the contents of the auxiliary address register 14. As the object receiver 3, you can use the receiver of any known type, for example, superheterodyne with a variable frequency of the local oscillator. The heterodyne receiver 17 should be configured to carry out the transfer of the input frequency band to the region of lower (eg, sound) frequencies when receiving radio signals.

The object driver of the message 9 and the driver 25 of the command message are configured to generate signals in the desired frequency band with a corresponding (external to them) selection of the carrier frequency. With this in mind, the object message shaper 9 and command message shaper 25 can be performed according to the standard transmitter scheme with the selected modulation type as the serial code of the message to be transmitted.

The remaining nodes and blocks of the considered hardware implementation of the proposed method are standard digital elements that are widely described in the technical literature and available on the commercial market. The centralized security system described above works as follows.

At a certain distance (for example, no more than 20 km) from the central monitoring station, a number of protected objects are located (Fig. 1). Such protected objects may be vehicles or real estate.

SUBSTITUTE SHEET (RULE 26) Each of the protected objects is connected via a corresponding radio channel with a central monitoring station. The central monitoring station generates individual control signals for each protected object transmitted by the binary code over the air as part of the so-called command messages. After receiving the command message at the corresponding guarded object, an acknowledgment message is generated confirming the receipt of the command message.

At protected sites, disturbing events can occur, which include, for example, a fire or an attack on this protected object by intruders. Security equipment located at this guarded facility detects alarm events and then sends the corresponding alarm message to the central monitoring station. According to the decrypted alarm message, the PCO determines which alarm event occurred at the guarded object and take appropriate measures, for example, in the event of a fire, a fire brigade is sent to the appropriate address.

However, if the guarded object was attacked by intruders, it is necessary to reckon with the fact that the security equipment at the guarded object can be suppressed, for example, mechanically broken and destroyed by the use of firearms and explosives. Therefore, an alarming message about an attack by attackers may not reach the PCO. The security system under consideration provides that each of the messages of a certain i-th protected object is supplied and, accordingly, arrives at the central monitoring station at strictly defined time points (tу, fø ... ti, p _> ti _{iP + 1} ...). These time points are calculated both in each guarded object and in the central monitoring station. When transmitting (at time tj _jP) next message using a pseudorandom algorithm selection equiprobable determined interval

SUBSTITUTE SHEET (RULE 26) time T between the start of transmission of this message and the start of transmission of the following message: t _{i> p +]} = t. _p + T (1)

The algorithm for the pseudo-random equiprobable choice of the time interval T is special for each of the protected objects, however, each of the algorithms for the pseudo-random equiprobable choice of the time interval T for the protected object is also known in the central monitoring station. Common to all algorithms for the pseudo-random equiprobable choice of the time interval T are three parameters: Tmin - the minimum allowable time interval;

T _MAX - the maximum allowable time interval; Δt is the time interval selection step.

Thus, the choice of the time interval T is reduced to the choice of an integer K _t in the range from 0 to (TMAKC-TMIN) / Δ _T. At the same time, pseudo-random equiprobable selection algorithms should provide an equal probability of choosing any of the integers within the given limits. Formula

(1) is converted to:

H _{P +} i ^{= t} i, _P + ^T msh + Kt - Δt (2)

The binary code of each message is transmitted on a pseudo-randomly selected carrier frequency F. Algorithms for the pseudo-random equiprobable choice of the carrier frequency F are specific for each of the protected objects, however, each of the algorithms for the pseudo-random equiprobable choice of the carrier frequency F for the protected object is also known in the PCO. Common to all algorithms for pseudo-random equiprobable selection of the carrier frequency F are three parameters: Fmin - the minimum allowable carrier frequency; F _MAX - maximum allowable carrier frequency; Δ _F is the step of the frequency grid.

SUBSTITUTE SHEET (RULE 26) The pseudo-random choice of the carrier frequency F is reduced to the choice of an integer K _F ranging from 0 to (F _MAKC -F _MИH ) / Δ _F - In this case, pseudo-random equiprobable selection algorithms should provide an equal probability of choosing any of the integers within the given limits. The carrier frequency F is determined by the formula: F = F _Mшi + K _F - Δ _F (3)

When transmitting, frequency modulation is used. For example, a logical zero is transmitted at a carrier frequency F, and a logical unit is transmitted at a frequency F + K-Δ _F. The integer K is a common constant value for both all protected objects, and for the central monitoring station. For example, K = 2.

If at a certain point in time at a certain carrier frequency no messages from the corresponding protected object were received in the CCA, then such an event of the CCC equates to the receipt of an alarm message about the attack of attackers on this protected object. Therefore, if at any secured object at the moment selected for sending a message, there are no conditions for the formation and submission of an acknowledgment or alarm message, then this protected object generates a so-called control message. Its admission to the central monitoring station indicates only that the corresponding protected object is in a normal state. Of course, the control message may also contain some additional information, for example, that the voltage of the battery has dropped significantly and is close to the allowable limit. However, it should be noted that the content of any message does not relate to the subject of this patent and will not be considered. Only the presence of four types of messages in the system is essential: command, acknowledgment, control and alarm.

SUBSTITUTE SHEET (RULE 26) Moreover, the structure of each message contains: - a synchronizing marker; information block (made, for example, using error-correcting coding); - check sum.

The number of bits in each type of message is strictly constant. The duration of the transmission of each discharge is the same.

Let us now consider in more detail the operation of the equipment (Fig. 2) installed on protected objects. A number of sensors 1 are installed at the guarded object (vehicle or real estate), each of which implements the assigned security function directly for it in the security zone established for it. For example, one of the sensors 1 can make sure that the garage door is closed and maintains its integrity in a secured summer cottage. Another sensor 1 monitors the integrity and closed state of one of the windows of the house, etc. The task of the sensors 1 is to fix certain events (including disturbing events) and transmit information about these events to the object control unit 2 (which can be, for example, a specially programmed microcontroller).

A signal from the object receiver 3 also arrives at the object control unit 2 (when any command message from the central monitoring station arrives at this protected object).

The object control unit 2 according to the information received from the sensors 1 and from the object receiver 3, prepares a message code (acknowledging, monitoring or alarm) to be transmitted next. After the set minimum acceptable time interval (Tmin) has passed from the moment the last message starts, the object control unit 2 issues a command to node 4

SUBSTITUTE SHEET (RULE 26) pseudo-random selection. By this command, the node 4 pseudo-random selection transmits:

- on the object register 5 frequency code K _F carrier frequency of the next message; - on the object register 6 times the code K _{t the} expected time interval T between transmitted messages. With the minimum allowable content of the object register 6 times (for example, all logical zeros) between transmitted messages, the minimum allowable time interval Tmin _{e is set} and with the maximum allowable contents of the object register 6 times (for example, all logical units) the maximum allowable time interval T _MAX between transmitted messaging.

In addition, the object control unit 2 resets the object time counter 7 and starts to send counting signals to it, with a period equal to the step Δ _t of the time interval selection. The equality of the contents of the object time counter 7 to the contents of the object register 6 times means that the set expected time interval T has passed from the moment of the previous message. Matching circuit 8 establishes the coincidence of the contents of the object counter 7 time and the object register 6 times, and then sends a signal to the object shaper 9 messages to the object control unit 2.

The object control unit 2 remembers the moment the signal arrives at it from the coincidence circuit 8. This moment the object control unit 2 considers as the moment of the beginning of transmission of the next message, because the signal from the matching circuit 8, the object driver of the message 9 starts transmitting the next message to the air. When sending a message to the radio

SUBSTITUTE SHEET (RULE 26) ₅ the carrier frequency F which code (K _F) enters the site-driver 9 messages output from the register 5, the frequency of on-site, and the serial code of the message in the incoming message site-driver 9 of object control unit 2. Upon completion of the transmission of the message, the object control unit 2 turns off the object shaper 9 of the message and switches to the standby mode for receiving a command message, which can be received in the object block 2 from the object receiver 3. In this case, the carrier frequency of the expected command message is set for the object receiver 3 from the output of the object 5 frequency register. In a system that implements the proposed method, there is always a single protected object that transmits a message to the ARC at a given carrier frequency F. Therefore, a command message from the ARC (at the same carrier frequency F) is sent strictly to a specific protected object (no address is required). After receiving the command to the object control unit 2, this object control unit 2 starts working out the contents of the received command, carrying out the required actions.

These actions are not the subject of the invention and are not specifically considered with a single exception: a command to change the expected time interval T is received. By this command, the maximum permissible time interval T _MAKC must be forcibly set on the guarded object - Therefore, to work out this command after node 4 pseudo-random selection in the object register 6 time receives the next code KT - the expected time interval T, from the object block 2 control to the same object register 6 time p steps in forcing the signal

SUBSTITUTE SHEET (RULE 26) object register b time maximum content (TMAK _S G

Tmin) / Δt-

Consider now the operation of the PCO equipment (Fig.Z). For simplicity, the block diagram of the PCO equipment in the implementation example (Fig. 3) does not take into account the possibility of simultaneously receiving messages from several protected objects (when using spaced carrier frequencies) in the PCO.

We begin the review of the operation of the PCO equipment at the expected time tj _{) P of} receiving the next message from some i-th guarded object. At this point in time, the contents recorded in the auxiliary time register 10 coincides with the current time of the central monitoring station, that is, with the counter 11 of the current time. This coincidence fixes the first comparison circuit 12 and generates a control signal supplied to block 13 of pseudo-random selection nodes. At the address arriving at the block 13 of the pseudo-random selection nodes from the auxiliary address register 14, in the block 13 of the pseudo-random selection nodes, the pseudo-random selection node whose operation algorithm corresponds to the operation algorithm of the pseudo-random selection node 4, which is part of the protected object, is received and received from which it is expected in PTsO. Thus, at the output of the block 13 of pseudo-random selection nodes, the set of signals appears that should be generated in the corresponding guarded object at the output of the pseudo-random selection node 4 during the formation of the next message. This set of signals goes to the central frequency register 15 and to the central time register 16. At the moment of time tj _{; P} in the monitoring station, the reception of a message from a certain i-th protected object should begin. This reception is carried out by a broadband heterodyne receiver 17. When receiving, there is a linear transfer of the input frequency domain to the region of more

SUBSTITUTE SHEET (RULE 26) low frequencies. That is, as a result of the conversion, instead of the carrier frequency F, there appears a certain frequency Fi that is uniquely associated with it by a linear transformation. From the output of the heterodyne receiver 17, the signals are fed to an analog-to-digital converter 18, where they are converted to digital form. Further, the received signals are fed to the digital filter unit 19. The code of the expected frequency Fj is transmitted to the same block of digital filters 19 from the output of the auxiliary frequency register 20. Using this code, the digital filter unit 19 creates several digital filters corresponding to the frequency of the expected signals. For the above K = 2, we can limit ourselves to five digital filters whose nominal frequencies are equal to: the expected frequency of reception of a logical zero Fi; the expected frequency of reception of a logical unit Fi + 2-Δ _F ; expected frequency receiving logic zero with regard to possible errors on the "+ Δ _F" (or expected frequency receiving logical unit in view of possible errors, _{"-Δ F") Fi + Δ} F; the expected frequency of receiving logical zero, taking into account the possible error on the "-Δ _F " Fi-Δ _F ; the expected frequency of reception of a logical unit, taking into account a possible error on "+ Δ _F " Fi + З-Δр.

In principle, using these five digital filters, a possible error of up to ± 3-Δ _F can be detected. in this case, the signal will be on only one digital filter. Then it is necessary to rebuild the digital filters, for example, by correspondingly changing the expected frequency of Fi reception.

The allocated frequency intervals must overlap to ensure the receipt of notifications near the boundaries of the intervals. The amount of overlap is determined when programming the operation of block 19

SUBSTITUTE SHEET (RULE 26) digital filters. In the system hardware implemented by the applicant enterprise, the digital filter unit 19 was built on the basis of a fast Fourier transform.

From the output of digital filter block 19, the signal is sent to decision block 21. If at the expected time for receiving a message at the expected frequency there is no signal reception, then decision block 21 includes a warning about an alarm event: no messages from a specific protected object.

If the digital filter unit 19 detects the presence of a signal in the desired frequency range, then the integration intervals must be set in the digital filter unit 19, the beginning and end of each of which must correspond to the beginning and end of the discharge transmission in the message of the protected object. Setting integration intervals is carried out when receiving a synchronizing message marker.

If the operation of the PCA equipment and the corresponding guarded object occurs completely synchronously, then the signal issued by the first comparison circuit 12 at the time ti _{) P} will indicate the beginning of message reception. However, it is impossible to achieve complete synchronization of the operation of various units of equipment in the absence of common synchronization signals. Therefore, a certain limited time shift is allowed between the beginning of the reception of the message and the beginning of the output signal of the first comparison circuit 12. The maximum permissible value of this shift ± δ can be estimated. That is, it can be considered acceptable that the reception of a message begins at any arbitrary time within

This time limit can, for example, be divided into a certain number of equal shares determined by the program of work

SUBSTITUTE SHEET (RULE 26) block 19 of digital filters, and choose the moment the message begins to receive the maximum integral function corresponding to finding the received signal in a certain frequency range. If, for example, logical zeros and logical units are transmitted alternately in the synchronization marker, then the signals will appear alternately at the outputs of one of the following filter pairs:

- with nominal frequencies Fi and Fi + 2-Δ _F ;

- with nominal frequencies Fi + Δ _F and Fi + 3-Δ _F ;

- with rated frequencies F _J -Δ _F AND F _I + Δ _F. The integration time in each of the digital filters is exactly equal to the time of receipt of one bit of the message. The more precisely the start and end of the integration time correspond to the start and end times of transmission of one bit of the message, the higher the integration result. From its maximum, it is possible to fairly accurately establish the correction τ, by which the moment ti _iP differs from the real moment t * i _{) P} , of the beginning of the reception of the message. Thus, the estimated time t _{i) P of the} start of reception is recorded in the auxiliary time register 10, a correction τ to this time moment is set in the digital filter block 19, and the expected value T of the time interval between the filing of the considered message of this protected object is stored in the central time register 16 and by filing the next message from the same guarded facility. According to this data, the central control unit 22 calculates the expected time t _{i) P +} i of receiving the next message from the i-th guarded object. In addition, the central control unit 22 updates the expected frequency value of the next message recorded in the central frequency register 15.

Then, the Central control unit 22 sequentially reads from the cells of the buffer memory 23 the values of the expected moments of reception

SUBSTITUTE SHEET (RULE 26) Messages from each of the remaining protected sites. Using the second comparison circuit 24, each of the read values is compared with the calculated expected time ti _{) P +} i of receiving the next message from the i-th guarded object. If the comparison reveals the possibility of blocking the message from the i-th protected object (taking into account the fact that a command message can be transmitted immediately after the end of this message) with a message from some other protected object or with a command message, then the second comparison circuit 24 gives about this signal to the Central control unit 22. Based on this signal, the central control unit 22 sets in the central time register 16 the content corresponding to the maximum allowable interval between submission of messages from one source (for example, all logical units), and then repeats the calculation of the expected time tj _{) P +} i of receiving the next message from the i-th protected object, taking into account the change in the contents of the central register 16 time. In addition, the central control unit 22 remembers that upon receipt of a message from the i-th protected object, it is necessary to submit a command message about the postponement of the next message from the i-th protected object.

When all the checks carried out the second comparison circuit 24, central control unit 22 writes the i-th cell buffer memory 23, calculated values of the expected moment _{tj> p +} i receive the next message from the i-th protected object and the carrier frequency of the communication.

It should be noted that the message continues to be received from the i-th protected object. The message bits are sequentially delivered to the deciding unit 21, where the content of the message is evaluated essentially. At the end of receiving the message, the decisive

SUBSTITUTE SHEET (RULE 26) unit 21 transmits a signal corresponding to the received message to the central control unit 22.

In this case, it can be revealed that an alarm message has been received or a control message has been received instead of an acknowledgment message. In both cases, the central control unit 22 includes a corresponding alarm, according to which an adequate solution is developed in the central monitoring station. The development of a specific adequate solution does not relate to the subject of this patent.

After the signal about the received message is received in the central control unit 22, the central control unit 22 checks whether it is necessary to generate a command message for the i-th guarded object. Such a message may be, in particular, a command message about the postponement of the next message by the i-th protected object. If this command message does not need to be generated, then the central control unit 22 checks if there are any requirements for the formation of any other command message. If it is necessary to transmit a command message, the central control unit 22 includes a command message generator 25, which, on an adjusted carrier frequency, transmits over the air a serial code of the corresponding command message.

Upon completion of the transmission of the command message (or after the fact of the absence of the need for its transmission to be detected), the central control unit 22 starts sequential interrogation of the cells of the buffer memory 23. Using the second comparison circuit 24, the cell of the buffer memory 23 is detected, in which the smallest moment of the expected time of receipt of the message is recorded. After that, from the buffer memory 23 is overwritten:

- the moment of the expected time of arrival of the next message - in the auxiliary register 10 time;

SUBSTITUTE SHEET (RULE 26) - the expected carrier frequency to the auxiliary frequency register 20;

- the number of the buffer memory cell is in the auxiliary register 14 addresses. After that, the central monitoring station is prepared to receive the next message from the protected object. The work of the PCO considered above is further completely repeated.

When using the proposed method retains all the positive properties of the prototype, however, the technical implementation of the proposed method is significantly simpler. This provides a significant increase in the signal-to-noise ratio due to the multiple narrowing of the passband of the receiving path in the PCO, which proportionally reduces the noise power in the received frequency band while maintaining the useful signal power. At the applicant enterprise, equipment was tested that implements radio communication methods corresponding to the prototype and the claimed technical solution. Tests have shown that when fulfilling the requirements to limit the radio frequencies used and the radio signal power, the use of the proposed technical solution allows, all other things being equal, to increase the maximum permissible distance between the guarded object and the PTOs more than twenty times.

Thus, the combination of known and newly introduced in the claimed method of actions on material objects allows us to solve the problem that the invention is aimed at, while ensuring the required technical result. The method is technically feasible and has novelty, which allows us to consider it as an invention.

SUBSTITUTE SHEET (RULE 26)

Claims

Claim

1. The method of radio communication between the guarded objects and the central security point, in which the centralized guard point for each guarded object identifies the need for the appropriate control signal, form a binary code for this control signal and transmit it over the air as part of a command message, which is received on the corresponding guarded in the object, in each of the protected objects they form in binary code and transmit to the central protection point over the air acknowledging, control or alarm messages, moreover, an acknowledgment message is generated after receiving a command message from the central guard station, an alarm message after an alarm event is detected at the guarded object, and a control message, in the absence of conditions for the generation of an acknowledgment and alarm message, identifies an alarm message at the central guard station according to the received alarm message the event that caused the formation of the alarm message, and make a decision that is adequate to the alarm event that occurred during transmission e from each protected object of any message - acknowledging, monitoring or alarming - determine the expected time interval T between the moments of the start of transmission of this and the next message of this protected object and the carrier frequency F of the next message, in order to select the expected time interval T use three coinciding for all Protected Objects Indicator: Minimum Allowable Time Interval Cumin _? the maximum allowable time interval T _MAKC And the step Δ _{t is the} choice of the time interval, and to select the carrier frequency F of the next message also use three indicators that are the same for all protected objects: the minimum allowable frequency Fmin, the maximum allowable frequency F _MAK c and the step Δ _{F of} the frequency grid,

SUBSTITUTE SHEET (RULE 26) the expected time interval T is determined by selecting, according to a pre-established algorithm for each protected object, a pseudo-random equiprobable choice of the number K _t within Q <K _T ≤ (T _MAKC -T _MИH ) / Δ _T and using the relation T = Tmin + KtΔ _t , and determination of the carrier frequency F of the next message is carried out by selecting, according to a similar pre-established algorithm for each protected object, a pseudo-random equiprobable choice of the number Kp within 0 <K _F ≤ (F _MAKC -FMINUΔF and using the relation

characterized in that in the centralized protection point each of the pseudorandom equiprobable algorithms pre-installed for the protected objects is stored and these algorithms are used to determine and subsequently remember the timing of the arrival of the next messages from each of the protected objects and the carrier frequencies of these messages, when forming messages, logic-zero to logic one by shifting the carrier frequency F by an integer K steps Δ _F grid frequency exceeding units and constant for all protected objects, when the current time approaches the memorized time of the next message from one of the protected objects, they receive broadband signals, transfer the input frequency band to the lower frequency region, perform analog-to-digital conversion using digital filtering methods the transfer of the input frequency band allocate frequency intervals close to those frequencies at which the symbols of the logical should be transmitted in the expected message zero and a logical unit, and in the absence of the expected message in the selected frequency areas, take measures adequate to the measures taken upon receipt of an alarm from the corresponding protected object

SUBSTITUTE SHEET (RULE 26) messages, if there is a message received by sequentially shifting the digital filtering time interval by a step shorter than the transmission time interval of one bit in the message, the moments of the change in the bits in the message and the shift in the message start time caused by the mismatch of the reference frequency of the generators as part of the central protection and guarded object, decode the received message and perform actions adequate to its content and taking into account the conditions that occur in the central security , check whether these actions require a control signal to be sent to the protected object, and if there is such a requirement, a command message containing the desired control signal is generated and transmitted at the frequencies of logical zero and logical units in the message received by the central security center, as amended taking into account receiving a message, the mismatch of the reference frequency of the generators as part of the centralized protection point and the guarded facility, and at the guarded facility at the end of the transmission of each message eniya for a specified period of time awaiting commands revenues from centralized protection at the same frequencies, which from a given protected object passed last post.

2. The method according to claim 1, characterized in that in the centralized security point, when determining the time of arrival of the next message from the protected object, the expected time interval for receiving the next message is compared with the previously expected time intervals for the receipt of messages from other protected objects, and the presence of these intervals is detected the expected time interval for receiving the next message, taking into account the duration of the additional time interval for submitting the command message, when t What overlays check for proximity of carriers

SUBSTITUTE SHEET (RULE 26) frequencies and when the proximity of the carrier frequencies is established, a change command is generated for the protected object under consideration for the formation time and / or carrier frequency of the next message, after which the corrected parameters are stored in the centralized protection center and at the protected object.

3. The method according to claim 2, characterized in that, with the help of the command generated in the centralized security center, the time interval T between the start of transmission of this and the next message from the corresponding protected object is increased to the maximum allowable value T _MAKC .

4. The method according to claim 1, characterized in that the digital filtering of messages at a centralized security point is carried out using a fast Fourier transform.

5. The method according to claim 4, characterized in that when using the fast Fourier transform, an acceptable frequency overlap is established in adjacent spectral regions, at least a step Δp of the frequency grid.

6. The method according to p. 1, characterized in that in the structure of each message allocate a synchronization marker, an information block made using noise-resistant coding, and a checksum.

SUBSTITUTE SHEET (RULE 26)