RU2351945C1 - Method of determination mobile object coordinates in closed premises and system for its realisation - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: system, realising offered method, contains radio-frequency identifiers, input reader transmitting radio modem with the antenna, electronic computer and receiving radio modem with the antenna. The input reader contains master oscillator, circulator, radio-frequency amplifier and phase detector. The transmitting radio modem contains lag line, generator of pseudorandom sequence, phase manipulator, adder, refactor, narrow-band filter and power amplifier. The radio-frequency identifier contains piezocrystal, microstrip antenna, busbars, electrodes.

EFFECT: increase of accuracy and reliability of monitoring of mobile objects in the closed premises by use of difficult signals with phase manipulation and trusty radio-frequency identifiers on the superficial ultrasonic waves.

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Description

The proposed method and system relates to automation and computer technology and can be used in the construction of automated warehouse management systems, namely to facilitate the search for goods, in the search systems for miners in mines after an accident, and to track staff movements around protected and important objects.

A known system for determining the coordinates of objects containing an antenna and a receiver of satellite navigation signals associated with an onboard computer (Utility Model Certificate No. 30.045 U1. Radio channel information transmission system. Paigin VP, Kireev Yu.P., etc., HB04 3/00, 2002).

A disadvantage of the known analogue system is the impossibility of determining the coordinates of a moving object when it is indoors: in a warehouse, in a hangar, in a tunnel. This is due to the fact that satellite navigation signals transmitted by GPS (Global Positioning System) satellites are not received by the satellite antenna due to the shielding properties of walls, roofs, buildings, and the Earth’s thickness.

A known method of identifying an object in which identifiers are located in people (moving objects), one reader is built into the lock (reading point), the reader contains a local area network controller connected to a central computer (B. Malashevich. Contactless identification. - J. “CHIP NEWS” - 2000, No. 8 (51), pp. 25-30).

This article describes the principle of operation of contactless radio frequency identifiers.

Electronic tags (identifiers) are based on housing integrated circuits manufactured by CMOS technology. Such a microcircuit has a permanent storage device (memory) or a reprogrammable memory in which the identification number of the object and its other characteristics are recorded. Chips together with a transceiver antenna can be installed in various cases in the form of a plastic card, key fob, key fob, disk, tablet label. The case design is determined by the purpose of the radio frequency identifier.

Plastic cards are produced for making passes in authorized access systems, tags for stickers on products in supermarkets and warehouses, key fobs for identifying keys or other valuable items, tokens for covert installation in products, tablet labels for covert installation in products. Tokens and tags can be installed covertly in concrete or painted over in the product, which makes it difficult to remove them to depersonalize the product.

The disadvantage of this method of determining the coordinates is that the coordinate of the location of the reader is determined. For example, when entering a protected area, an employee places his pass in the reader, the reader reads the pass code, sends it over the local network to the central computer, where this code is checked to restrict access to this room. The computer sends a door lock unlock code. In this case, the computer records the time, employee code, room number in which the employee is located in the database. In other words, the coordinates of the employee (as an object) are determined accurate to the size of the room, enterprise. Another drawback is the need for a person to interact with the radio frequency identifier with the reader by manually entering a pass (card) with the built-in radio frequency identifier in the reader.

There is a known method of identifying an object in which radio frequency identifiers are installed on the sides of moving objects (cars or containers), readers are installed on the border of a railway station near railway lines (reading point) and contain a local area network controller connected to a central computer (Automatic container identification system and “Palma” vehicles. - Promotional brochure of TsNIRTI, Moscow).

The advantage of this method is the remote reading of information by the reader from the radio frequency identifier. The reading distance is 13 m with a power source in the radio frequency identifier and 5 m without a power source. The disadvantage of this method is that it is aimed at identifying (determining the number and accessories) of railway cars, containers, vehicles and identifies the point of identification without determining the coordinates of the reader, i.e. the accuracy of the coordinates of the object (car) is equal to the size of the railway station itself and its entire area under the tracks (several km ² ).

There are also known methods for determining the coordinates of a moving object (RF patents Nos. 2,013.785, 2.284.542; US Patent 4,916,455; French patent 2,630,565; WO patent 98/53,431; Burlakov V. Radio frequency identification. Electronic components. 2005, No. 5, p. 55-60 and others).

Of the known methods and systems closest to the proposed are the "Method for determining the coordinates of a moving object in enclosed spaces and a system for its implementation" (patent No. 2.284.542, G01S 1/00, 2004), which are selected as prototypes.

Known technical solutions provide an increase in the accuracy of determining the coordinates of a moving object to the size of the mesh cell with a constant step plotted on the floor plan.

An object of the invention is to increase the reliability and reliability of monitoring moving objects in enclosed spaces by using complex signals with phase shift keying and reliable radio frequency identifiers based on surface acoustic waves.

The problem is solved in that the method of determining the coordinates of a moving object in enclosed spaces using electronic identifiers and readers, according to which, in accordance with the closest analogue, the reader is fixed on the moving object, and electronic identifiers are fixed on the structural elements of the room, when approaching the electronic identifier of the moving object the code of the electronic identifier is read by its reader and, together with the code of the moving object, is transmitted via a radio modem to a computer radio modem, while the position of electronic identifiers is determined by a grid with a constant step plotted on the floor plan, the codes of electronic identifiers and the coordinates codes of their positions are stored in a computer in which the coordinates of the moving object are determined and its position displayed on the monitor together with the floor plan is different from the closest analogue in that, as an electronic identifier, a piezocrystal with an aluminum interdigital transducer deposited on its surface connected to a mic Stripline antenna, and a set of reflectors, is approached to the electronic identifier of the mobile object his reader is irradiated with an electronic identifier harmonic oscillation of the carrier frequency ω _1, take it to the electronic identifier is converted into an acoustic wave, ensure its spread over the surface of the piezoelectric crystal and back reflection is converted reflected acoustic wave again into a complex signal with phase shift keying, the internal structure of which corresponds to the structure of the interdigital reobrazovatelya, re-emit it in the air, taking the reader of the mobile object, increase in amplitude is performed synchronous detection at the frequency ω _1, allocate a low-frequency voltage corresponding to the code of the electronic identifier, delay it for a time equal to the duration of an electronic identifier code summed with the moving object code, multiplied harmonic oscillation of the carrier frequency ω ₁ on itself, isolated harmonic oscillation of the carrier frequency ω ₁ = 2ω _2, manipulate it by the total code phase, y ilivayut power generated complex signal with phase shift keying, emit ether receiving radio modem computers, divide the phase two, isolated harmonic oscillation of the carrier frequency ω ₁ is multiplied by its phase two, isolated harmonic oscillation of the carrier frequency ω _2, shift it to 90 ° phase and is used for synchronous detection of a complex signal with phase shift keying at a frequency of ω ₂ .

The problem is solved in that the system for determining the coordinates of the position of a moving object in enclosed spaces, containing, in accordance with the closest analogue, electronic identifiers located on structural elements of the room, a reader mounted on a moving object, transmitting a radio modem associated with the reader, and a receiving radio modem, connected to a computer, while the position of electronic identifiers is determined by a grid with a constant step plotted on the floor plan, electronic identifier codes in and the coordinate codes of their position are stored in a computer, in which the coordinates of the moving object are determined and its position is displayed on the monitor together with the floor plan, differs from the closest analogue in that the reader is made in the form of series-connected master oscillator, circulator, the input-output of which with a transceiver antenna, a high-frequency amplifier and a phase detector, the second input of which is connected to the output of the master oscillator, the transmitting radio modem is made in the form of series-connected output to the phase detector of the delay line, the adder, the second input of which is connected to the output of the pseudo-random sequence generator, the phase manipulator and the power amplifier, the output of which is connected to the second input of the circulator, connected in series to the output of the master oscillator multiplier, the second input of which is connected to the output of the master oscillator , and a narrow-band filter, the output of which is connected to the second input of the phase manipulator, the receiving radio modem is made in the form of series-connected receivers an antenna, a high-frequency amplifier, a phase divider into two first narrow-band filters, a phase doubler, a second narrow-band filter, a 90 ° phase shifter and a phase detector, the second input of which is connected to the output of the high-frequency amplifier, and the output is connected to a computer, the electronic identifier is made in in the form of a piezocrystal with an aluminum thin-film interdigital transducer deposited on its surface connected to a microstrip antenna and a set of reflectors, the interdigital transducer contains two combs chat systems of electrodes, electrodes of each of the combs are connected to each other by buses connected to a microstrip antenna.

The structural diagram of a system that implements the proposed method is presented in figure 1. Functional diagram of the radio frequency identifier shown in figure 2. The structural diagram of the reader and the transmitting radio modem is presented in figure 3. The block diagram of the receiving radio modem is presented in figure 4. Timing diagrams explaining the operation of the system are shown in FIG.

The system for determining the coordinates of a moving object in enclosed spaces contains radio frequency identifiers 1, a reader 2, a transmitting radio modem 3 with a transceiving antenna 8, a receiving modem 5 with a receiving antenna 23 connected to a computer 4.

The radio frequency identifier is made in the form of a piezoelectric crystal 18 with an aluminum thin-film interdigital transducer deposited on its surface connected to a microstrip antenna 19 and a set of reflectors 22. The interdigital transducer of surface acoustic waves (SAW) contains two comb systems of electrodes 20, bus 21, which connect the electrodes of each of the combs to each other. Tires 21 are in turn connected to the microstrip antenna 19.

The reader 2 is made in the form of series-connected master oscillator 6, circulator 7, the input-output of which is connected to the transceiver antenna 8, high-frequency amplifier 9 and phase detector 10, the second input of which is connected to the output of master oscillator 6.

The transmitting radio modem 3 is made in the form of a delay line 11 connected in series to the output of the phase detector 10, an adder 13, the second input of which is connected to the output of the pseudorandom sequence generator 12, the phase manipulator 16 and the power amplifier 17, the output of which is connected to the second input of the circulator 7 connected in series to the output of the master oscillator 6 of the multiplier 14, the second input of which is connected to the output of the master oscillator 6, and a narrow-band filter 15, the output of which is connected to the second phase input manipulator 16.

The receiving radio modem 5 is made in the form of a high-frequency amplifier 24, a phase divider 25, a first narrow-band filter 26, a phase doubler 27 of a second narrow-band filter 28, a phase shifter 29 by 90 °, and a phase detector 30, the second input of which is connected in series to the output of the receiving antenna 23 connected to the output of the high-frequency amplifier 24, and the output is connected to the computer 4.

The method of determining the coordinates of a moving object in enclosed spaces is implemented as follows.

A plan of a building, warehouse, or mine is being prepared (or taken). The distances according to this plan are measured between the radio frequency identifiers 1, which should serve as coordinate marks. For example, for a warehouse (hangar), in which there are no internal partitions, you can put a grid on the plan with a constant step between the cells. In the coordinate system of this plan, the coordinates of these cells are determined. The coordinates of the cells are recorded in the radio frequency identifiers, the identifiers are accordingly marked by selecting the internal structure of the interdigital transducers. Appropriate marking is made on the floor and holes are drilled into which the corresponding identifiers are laid, holes are concreted. You can pull a wire under the ceiling, on which to fix identifiers 1. In the shaft, identifiers 1 can be fixed with the corresponding step on the ceiling of the drift.

Figure 1 presents a system that implements the proposed method, in which the radio frequency identifiers 1 contain codes for their coordinates and are mounted on building structures. In the memory of the reader 2 write the code of the moving object (warehouse operator, miner, important cargo, loader) and fix it, respectively, on the person’s belt, on the loader, on the load.

The master oscillator 6 of the reader 2 generates a high-frequency oscillation (Fig.5, a):

U ₁ (t) = υ ₁ Cos (ω ₁ t + φ ₁ ), 0≤t≤T ₁ ,

where υ ₁ , ω ₁ , φ ₁ , T ₁ - amplitude, carrier frequency, initial phase and duration of high-frequency oscillations,

which through the circulator 7 enters the antenna 8, is radiated by it and irradiates the nearest radio frequency identifier 1. The high-frequency harmonic oscillation at the frequency ω _{1 is} captured by the microstrip antenna 19 tuned to the frequency ω ₁ , is converted by the interdigital transducer into an acoustic wave, which propagates through the surface of the piezocrystal 18, is reflected from the reflectors 22 and again converted into a complex signal with phase shift keying (QPSK) (figure 5, c):

U ₂ (t) = υ ₂ Cos (ω ₁ t + φ _к1 (t) + φ ₁ ), 0≤t≤T ₁ ,

where φ _k1 (t) = {0, π} is the manipulated component of the phase, which displays the law of phase manipulation in accordance with the modulating code M ₁ (t) (Fig. 5, b), which displays the coordinates of the identifier, and φ _k1 (t) = const at k · τ _e <t <(k + 1) · τ _e and can change stepwise at t = k · τ _e , i.e. at the borders between elementary premises (k = 1, 2, ..., N-1);

τ _e , N - the duration and number of chips that make up the signal of duration T ₁ (T ₁ = N · τ _e ).

In this case, the internal structure of the formed complex QPSK signal is determined by the topology of the interdigital transducer, has an individual character and contains information about the location of the identifier in the corresponding structure.

The generated complex QPSK signal U ₂ (t) is radiated by the microstrip antenna 19, captured by the receiving antenna 8, and fed through the circulator 7 and the high-frequency amplifier 9 to the information input of the phase detector 10. A high-frequency oscillation is applied to the reference input of the latter U ₁ (t) (Fig. 5, a) from the output of the master oscillator 6. At the output of the phase detector 10, a low-frequency voltage is generated (Fig. 5, g):

U _н1 (t) = υ _н1 · _{Cosφ к1} (t) 0≤t≤T ₁ ,

where υ _н1 = 1 / 2υ ₁ · υ ₂ ,

proportional to the modulating code M ₁ (t) (Fig. 5, b).

This voltage is supplied to the delay line 11, where it is delayed for a time τ _З equal to the duration τ _{1 of the} modulating code M ₁ (t), and is supplied to the first input of the adder 13. The code of a moving object (warehouse operator, loader, miner) is supplied to the second input of the last ) from the output of the generator 12 of a pseudo-random sequence (PSP) of duration τ ₂ . At the output of the adder 13, a total modulating code M ₂ (t) is generated (Fig. 5, e), consisting of an identifier coordinate code and a moving object code, of duration τ = τ ₁ + τ ₂ . The modulating code M ₂ (t) is supplied to the first input of the phase manipulator 16.

High-frequency oscillation U ₁ (t) (Fig. 5, a) simultaneously arrives at two inputs of the multiplier 14, at the output of which a voltage is generated (Fig. 5, d):

U ₃ (t) = υ ₃ Cos (ω ₂ t + φ ₂ ), 0≤t≤T ₁ ,

where υ ₃ = 1 / 2υ ₁ ² ;

ω ₂ = 2ω ₁ ; φ ₂ = 2φ _1.

This voltage is supplied to the second input of the phase manipulator 16, at the output of which a complex signal with phase shift keying (PSK) is generated (Fig. 5, g):

U ₄ (t) = υ ₄ · Cos [ω ₂ t + φ _к2 (t) + φ ₂ ], 0≤t≤T ₁ ,

which after amplification in the power amplifier 17 through the circulator 7 enters the transceiver antenna 8, is radiated by it, is captured by the receiving antenna 23 and through the high-frequency amplifier 24 is fed to the input of the phase divider 26 into two.

It should be noted that the manipulated phase component φ _к2 (t) in the voltage U ₄ (t) can be represented in the following form:

φ _k2 (t) = Δφ

where Δφ = 90 °,

in (t) is the function that determines the law of phase change.

To simplify, we assume that the function in (t) is periodic with a period T equal to twice the value of the duration τ _{e of the} elementary premises (T = 2τ _e ), i.e.:

The expansion of the function in (t) in a Fourier series has the following form:

At the output of the divider 25 phase into two, the following voltage will take place:

.

.

With binary phase manipulation, i.e. for φ _к2 (t) = {0, π}, Δφ = 90 °, the PSK signal U ₄ (t) does not contain the oscillations of the carrier frequency ω ₂ in its spectrum, since Cos90 ° = 0.

At the output of the phase divider 25 into two, a component of the carrier frequency ω ₂ appears in the spectrum of the obtained voltage U ₅ (t), since Cos (Δφ / 2) -Cos45 ° = 0.707 and the voltage will have the following form (Fig. 5, h):

where υ ₆ = 0.707 · υ ₅ .

This voltage is allocated by a narrow-band filter 26 and is fed to the input of the phase doubler 27, at the output of which a harmonic oscillation is formed:

U ₇ (t) = υ ₇ · Sin (ω ₂ t + φ ₂ ), 0≤t≤T ₁ ,

where υ ₇ = 1/2 · υ ₅ ² ,

which is allocated by the narrow-band filter 28 and enters the input of the phase shifter 29 by 90 °. At the output of the latter, harmonic oscillation is formed (Fig. 5, and):

,

,

which is used as the reference voltage and is supplied to the reference input of the phase detector 30, to the information input of which the PSK signal U ₄ (t) (Fig. 5, g) is output from the output of the high-frequency amplifier 24.

As a result of synchronous detection at the output of the phase detector 30, a low-frequency voltage is generated (figure 5, k):

U _n2 (t) = υ _n2 · _{Cosφ k2} (t), 0≤t≤T ₁ ,

where υ _Н2 = 1 / 2υ ₄ · υ ₇ ,

proportional to the total modulating code M ₂ (t) (Fig. 5, e).

The information contained in the modulating code M ₂ (t) is processed, stored and displayed on the monitor together with the plan of the building (structure). Thus, the position of the moving object in an enclosed space is continuously monitored over time.

Such information can be of particular importance for monitoring and recording the work of warehouse and arsenal personnel with secret and especially dangerous equipment, since the position of such equipment in the room will be constantly monitored.

Thus, the proposed method and system in comparison with prototypes and other technical solutions of a similar purpose provide an increase in the reliability and reliability of continuous monitoring of moving objects in enclosed spaces. This is achieved by using complex phase-shift keyed signals and reliable radio frequency identifiers on surface acoustic waves.

Radio-frequency identifiers are made in the form of a piezocrystal with an aluminum thin-film interdigital transducer deposited on its surface connected to a microstrip antenna and a set of reflectors.

The principle of operation of interdigital transducers is based on the fact that the electric fields in space and time created by a system of electrodes in a piezoelectric crystal cause elastic strains due to the piezoelectric effect, which propagate in the crystal in the form of surface acoustic waves (SAWs).

Surface acoustic waves are waves propagating along the surface of solids in a relatively thin surface layer. The propagation velocity of surfactants in crystals is approximately five orders of magnitude lower than the propagation velocity of electromagnetic waves. This means that on the centimeter of the crystal, you can place information that will fill a kilometer-long cable. The high information capacity of devices based on surface acoustic waves and the absence of power sources provide high reliability of the operation of radio frequency identifiers, which provide the ability to remotely read the information that carries them an unlimited number of times over a long time.

Complex signals with phase shift keying offer great opportunities in messaging technology. They allow the use of structural selection. This means that it becomes possible to separate signals operating in the same frequency band and at the same time intervals.

From the point of view of detection, FMN signals have energetic and structural secrecy.

The energy secrecy of complex QPSK signals is due to their high compressibility in time and spectrum with optimal processing, which reduces the instantaneous radiated power. As a result of this, a complex QPSK signal at the receiving point may be masked by noise and interference. Moreover, the energy of the QPSK signal is by no means small, it is simply distributed over the time-frequency domain so that at each point in this region the signal power is less than the power of noise and interference.

The structural secrecy of complex QPSK signals is caused by a wide variety of their forms and significant ranges of parameter values, which makes it difficult to optimize or at least quasi-optimal processing of complex QPSK signals of an a priori unknown structure in order to increase the sensitivity of the receiving device.

For decoupling of radio frequency identifiers and radio modems, different frequencies ω ₁ and ω ₂ = 2ω _{1 were} selected.

Claims (2)

1. A method for determining the coordinates of the position of a moving object in enclosed spaces using electronic identifiers and readers, according to which the reader is fixed on the moving object, and electronic identifiers are fixed on the structural elements of the room, when approaching the electronic identifier of the moving object, the electronic identifier code is read by its reader and together with the code of the moving object is transmitted through the radio modem to the radio modem of the electronic computer (computer), while The life of electronic identifiers is determined by a grid with a constant step plotted on the floor plan, the codes of electronic identifiers and the coordinates codes of their positions are stored in a computer in which the coordinates of the moving object are determined and their position is displayed on the monitor together with the floor plan, characterized in that as electronic the identifier is used a piezocrystal with an aluminum interdigital transducer deposited on its surface connected to a microstrip antenna and a set of reflectors, etc. approximation to the electronic identifier of the mobile object his reader is irradiated with an electronic identifier harmonic oscillation of the carrier frequency ω _1, take it to the electronic identifier is converted into an acoustic wave, ensure its spread over the surface of the piezoelectric crystal and back reflection is converted reflected acoustic wave back to the complex signal with phase shift keying , the internal structure of which corresponds to the structure of the interdigital transducer, re-emit it on the air, take ayut reader moving object, increase in amplitude is performed synchronous detection at the frequency ω _1, allocate a low-frequency voltage corresponding to the code of the electronic identifier, delay it for a time equal to the duration of an electronic identifier code summed with the moving object code multiplied harmonic oscillation carrier itself on itself isolated harmonic oscillation of the carrier frequency ω ₁ = 2ω _2, manipulate it by the total code phase, increase in power generated complex Sig l with a phase shift keying emit ether receiving radio modem computers, divide the phase two, isolated harmonic oscillation of the carrier frequency ω ₁ is multiplied by its phase two, isolated harmonic oscillation of the carrier frequency ω _2, is shifted its phase by 90 ° and uses for synchronous detection of a complex signal with phase shift keying. 2. A system for determining the coordinates of the position of a moving object in enclosed spaces, containing electronic identifiers located on the structural elements of the room, a reader mounted on a moving object, a transmitting radio modem associated with the reader, and a receiving radio modem connected to an electronic computer (computer) , while the position of electronic identifiers is determined by a grid with a constant step plotted on the floor plan, codes of electronic identifiers and coordinate codes of their position are located in the computer, in which the coordinates of the moving object are determined and its position is displayed on the monitor together with the floor plan, characterized in that the reader is made in the form of sequentially connected master oscillator, circulator, the input-output of which is connected to the transceiver antenna, high-frequency amplifier and phase a detector, the second input of which is connected to the output of the master oscillator, the transmitting radio modem is made in the form of a delay line, adder connected in series to the output of the phase detector, the second input of which is connected to the output of the pseudo-random sequence generator, phase manipulator and power amplifier, the output of which is connected to the second input of the circulator, connected in series to the output of the master oscillator of the multiplier, the second input of which is connected to the output of the master oscillator, and a narrow-band filter, the output of which is connected to the second the input of the phase manipulator, the receiving radio modem is made in the form of a series-connected receiving antenna, high-frequency amplifier, phase divider a, a first narrow-band filter, a phase doubler, a second narrow-band filter, a 90 ° phase shifter, and a phase detector, the second input of which is connected to the output of a high-frequency amplifier, and the output is connected to a computer, the electronic identifier is made in the form of a piezocrystal with an aluminum thin-film deposited on its surface an interdigital transducer associated with a microstrip antenna and a set of reflectors, an interdigital transducer contains two comb systems of electrodes, the electrodes of each of the combs with We are united with each other buses, connected to the microstrip antenna.

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