KR20090011107A - Apparatus and metnod for discriminating vehicle entry lane using rfid - Google Patents

Abstract

An apparatus and a method for discriminating an entry lane of a vehicle are provided to accurately discriminate an entry lane number of a vehicle to which a tag is attached, by using a phase interference method without installing additional master equipments for waking up each of RFID readers. Two reader antennas(100,102) perform RF(Radio Frequency) transmission/reception and phase detection respectively. An RF processing unit(140) demodulates RF response signals received through the reader antenna for RF transmission/reception. A phase difference detector(160) detects a phase difference between the RF response signals and generates and outputs a lane identification signal. A distribution unit(120) distributes the RF response signals to the RF processing unit and the phase difference detector. A switching unit(130) connects the RF reader antenna for transmission and reception to the distribution unit or the RF processing unit selectively. A reader control unit(170) extracts tag identification information from the RF response signal and processes the tag identification information.

Description

Apparatus and Metnod for Discriminating Vehicle Entry Lane Using RFID}

The present invention relates to an apparatus and method for discriminating an entry lane of a vehicle using RFID, and more particularly, an active RFID system applied to a toll gate or a port of a toll road, and an entry lane of a tagged vehicle or container using a phase interference method. The present invention relates to an apparatus and method for determining a lane of entry of a vehicle using RFID to accurately determine a number.

In general, radio frequency identification (RFID) recognizes, tracks, and recognizes tagged objects, animals, and people by using radio frequency to read or record information from tags that have unique identification information. And technologies that enable management. An RFID device includes a plurality of tags (electronic tags or transponders, hereinafter simply referred to as tags) attached to an object or an animal with unique identification information and an RFID reader or interrogator for reading or writing information on the tags. It is composed. These RFID devices are classified into mutual induction and electromagnetic waves according to the intercommunication method between the reader and the tag, and are classified into active and passive types according to whether the tag operates with its own power. Shortwave, Very High Frequency (VHF), Ultra-High Frequency (UHF), and Super-High Frequency (SHF) types are classified. In accordance with the above classification, various kinds of standards are enacted or in preparation for enactment.

Meanwhile, in a toll road or a port such as a highway, it is necessary to accurately determine the number of lanes to which a vehicle or a container enters in order to settle costs, track logistics, or manage various kinds of vehicles. It adopts an active RFID device using 5.6 GHz belonging to 433 MHz or SHF band.

FIG. 1 illustrates an example applied to a port, for example, a port, for explaining a principle of discriminating an entry lane of a vehicle using a conventional RFID. As shown in FIG. 1, a plurality of lanes (a total of four lanes in this embodiment) in which the trailer-loading trailers Tr1-Tr4 enter and exit are partitioned and the base line BL of each lane. In place, for example, one RFID reader is installed at the center, and Ant1-Ant4 denotes antennas of RFDI readers installed in lanes, respectively. The reader antennas Ant1-Ant4 radiate radio waves in a spherical or fan shape toward the front.

On the other hand, the width of each lane is, for example, about 5 to 8 meters, and in the case of a trailer, since the body is very long, the tag is placed at a considerable distance from the base line BL, for example, 20 to 40 meters ahead. In this case, the interference of radio waves from tags of other lanes is prevented by adjusting the intensity of the transmission output in consideration of the tag recognition distance, the width of each lane, and the radio wave radiation pattern of the reader antenna.

However, since the recognition distance of the tag is considerably longer than the width of the lane, no matter how precisely the intensity of the transmit power is controlled, the radio waves emitted from the leader antenna of the lane are inevitably immediately adjacent to each other as shown in FIG. It spreads to lanes or lanes next to it. Accordingly, for example, the response antenna from the tag attached to the trailer (or the container loaded therein) Tr1 and Tr2 that enters lane 1 and lane 2 is received at the reader antenna Ant1 of one lane, for example. Similarly, the three-lane reader antenna Ant3 receives all the response radio waves from the tags attached to the trailers (or containers loaded therein) Tr2 and Tr4 that enter lanes 2 and 4.

As a result, according to the conventional apparatus for determining the lane of entry using RFID, no matter how precisely the intensity of the transmit power of the RFID reader is adjusted, since the radio waves of the vehicle entering the own lane and the adjacent lane are all received, other lanes are received. There was a problem in that the accuracy of the recognition was inferior, such as mistaken for entering the own lane with respect to the vehicle entering. Moreover, in the case of adjusting the intensity of the transmission power, the intensity of the transmission power is changed from time to time due to seasonal and environmental factors such as snow, rain, fallen leaves and dust. The distance also changed from time to time, so there was a problem that the accuracy of recognition was reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and is an active RFID system applied to a toll gate or a port of a toll road, and accurately determines an entry lane number of a tagged vehicle or container using a phase interference method. An object of the present invention is to provide an apparatus and method for discriminating an entry lane of a vehicle using RFID.

An apparatus for determining a lane of entry of a vehicle using RFID according to an aspect of the present invention for achieving the above object is provided in pairs at predetermined intervals in each lane of a toll gate or a port access road of a toll road, and is used for RF transmission / reception and phase. Two reader antennas each functioning for detection; Modulates a wake-up signal or a command signal and outputs it through the RF transmitting / receiving reader antenna, and receives it through the RF transmitting / receiving reader antenna after being transmitted from a tag attached to an entering vehicle or container. An RF processor for demodulating the received RF response signal; A phase difference detector for detecting a phase difference between the RF response signal received through the RF transmission / reception reader antenna and the phase detection reader antenna, respectively, and outputting a lane identification signal; Distribution means for distributing and transmitting the RF response signal received from the RF transmitting / receiving reader antenna to the RF processing unit and the phase difference detector; Switching means for alternatively connecting the RF transmitting / receiving reader antenna to the distribution means and the RF processing unit, and whether or not the RF response signal currently input by the lane identification signal is transmitted from a vehicle in its lane; And a reader controller which extracts and processes tag identification information from the RF response signal when it is transmitted from the vehicle in the lane after the determination.

In the above-described configuration, the switching means is composed of a front end RF switch and a rear end RF switch, wherein the front end RF switch alternatively connects the RF transmitting / receiving reader antenna to the rear end RF switch and distribution means, and the rear end. An RF switch alternatively connects the RF processor to the front end RF switch and the distribution means. The distribution means may consist of a power divider or a directional coupler.

On the other hand, the rear end of the phase detection reader antenna is preferably provided with an attenuator for matching the level of the received RF response signal with the level of the RF response signal output from the distribution means. Alternatively, an amplifier may be further provided at the rear end of the distribution means to adjust the level of the RF response signal output therefrom to be equal to the level of the RF response signal received from the phase detection reader antenna.

In addition, the lane identification signal is the phase difference signal, and in this case, the reader controller determines whether the RF response signal currently input according to a result of comparing the phase difference signal with a reference phase difference signal is transmitted from the vehicle of the lane. Judge. In contrast, the phase difference detector compares the phase difference signal with a reference phase difference signal provided from the reader controller to determine whether the RF response signal currently input is transmitted from the vehicle of its lane, and then identifies the lane. It can also be provided directly as a signal. In this case, the phase difference detector sends the phase difference signal.

에 의해 검출하되, φ는 상기 위상차를 나타내고, Ｄ는 상기 RF 송/수신용 리더 안테나와 상기 위상 검출용 리더 안테나 사이의 거리를 나타내고, λ는 입사파의 파장을 나타내며, θ는 상기 입사파의 입사각을 나타낸다.

Where ? Represents the phase difference, D represents the distance between the RF transmitting / receiving reader antenna and the phase detecting reader antenna, λ represents the wavelength of the incident wave, and θ represents the incident wave. The incident angle is shown.

According to another aspect of the present invention, there is provided a method for determining a lane of entry of a vehicle using RFID, which is installed in pairs at predetermined intervals in each lane of a toll gate or a port entrance and exit of a toll road, and functions for RF transmission / reception and phase detection, respectively. It is performed by an RFID reader having two reader antennas to determine a lane to enter a vehicle, and is transmitted from an active tag attached to a vehicle or a container and is respectively transmitted through the RF transmission / reception reader antenna and the phase detection reader antenna. According to a result of comparing the phase difference of the received RF response signal with the reference phase difference, it is determined whether the currently input RF response signal is transmitted from the vehicle of the lane.

In the above configuration, the phase difference is,

에 의해 검출하되, φ는 상기 위상 차를 나타내고, Ｄ는 상기 RF 송/수신용 리더 안테나와 상기 위상 검출용 리더 안테나 사이의 거리를 나타내고, λ는 입사파의 파장을 나타내며, θ는 상기 입사파의 입사각을 나타낸다.

But the detection by, φ is the phase represents the difference, D represents the distance between the RF transmitting / receiving the reader antenna and the phase detection reader antenna, λ denotes a wavelength of the incident wave, θ is the incident wave Represents the incident angle of.

On the other hand, when there are two or more RFID readers, one of them has a function as a master reader and a slave reader, and when serving as the master reader, the slave reader after transmitting a wake-up signal to all slave readers and tags. The slave leaders may transmit command signals in a preset order while being synchronized by the wake-up signal.

In this case, the intensity of the output of the wake-up signal is preferably greater than the intensity of the output of the command signal. Furthermore, the slave reader may output the command signal simultaneously with other slave readers within a range in which the output of the command signal does not interfere with other slave readers.

According to the apparatus and method for determining the entry lane of a vehicle using RFID according to the present invention, the entry lane number of a tagged vehicle or container is obtained by using a phase interference method in an active RFID system applied to a toll gate or a port of a toll road. Can be determined accurately.

In addition, the configuration of the system can be simplified because it is not necessary to install a separate master equipment to wake up each RFID reader.

Hereinafter, with reference to the accompanying drawings will be described in detail a device and method for determining the lane of entry using a RFID according to an embodiment of the present invention.

2 is a view for explaining the principle of the phase interference method used in the apparatus and method for determining the vehicle lane using the RFID of the present invention. As illustrated in FIG. 2, in the apparatus and method for determining a lane of entry of a vehicle using RFID according to the present invention, an RFID reader (not shown) is installed at a baseline of each lane of a toll gate or a port entrance to a toll road, and each RFID is provided. A total of two reader antennas Ant21 and Ant22 are installed in the reader side by side at predetermined intervals, for example, within an interval of 1 to 2 meters, preferably at intervals of several tens of centimeters.

In this configuration, the radio wave incident from the tag of the vehicle entering the magnetic lane is emitted from the tag almost at right angles to the base line BL (since there is a considerable distance between the reader antenna and the tag, each reader antenna Ant21, The radio wave received at (Ant22) enters the polarized wave and reaches almost parallel to each other, so that the arrival time is almost the same, so that no phase difference occurs. On the other hand, the radio wave incident from a tag attached to a vehicle entering another adjacent lane has a predetermined angle with respect to each of the reader antennas Ant21 and Ant22, that is, θ based on a vertical line with respect to the base line BL. Incident at an angle (these incident waves are also incident almost in parallel), whereby a phase difference φ exists between the radio waves incident on the left reader antenna Ant1 and the right reader antenna Ant2. When this is expressed as an equation, Equation 1 below is obtained.

In Equation 1 above, D represents a distance between two reader antennas Ant21 and Ant22, λ represents a wavelength of an incident wave, θ represents an angle of incidence of radio waves, and φ represents a phase difference of measured radio waves. . Here, since the radio waves incident on the reader antennas Ant21 and Ant22 are sinusoidal waves, the distance difference (arrival time difference) in FIG. 1 is represented as a phase difference as a result. The phase difference is converted into a voltage after being detected by a phase detector described later and output. Therefore, if the phase difference of the radio wave incident to the two reader antennas Ant21 and Ant22 is detected, it is accurately determined whether the current radio wave is transmitted from the vehicle entering the lane or from the vehicle entering the other lane. You can do it. Thus, in the present invention, since the radio waves transmitted from the vehicle entering the lanes and the adjacent lanes can be accurately distinguished, the intensity of the transmit power of the reader antenna can be sufficiently increased in consideration of changes in the transmit power according to seasonal and environmental factors. As a result, the recognition rate can be improved.

3 is a flowchart illustrating a method for determining a lane of entry of a vehicle using RFID according to the present invention, and FIG. 4 is a flowchart illustrating a communication order of respective RFID readers in an apparatus and method for determining a lane of entry of a vehicle using RFID according to the present invention. It is a figure for demonstrating a method. As shown in FIG. 3, in the method of determining a lane of entry of a vehicle using RFID according to the present invention, in adopting a plurality of RFID readers for lane discrimination, separate wired or wireless master equipment for maintaining synchronization therebetween is provided. It provides a master function to one of the RFID readers provided for lane discrimination without matching. Accordingly, the RFID reader combines the functions of the master reader and the slave reader (hereinafter referred to as 'master / slave reader'). do.

On the other hand, since the active RFID system uses a single carrier frequency, when each slave reader simultaneously transmits a signal, interference occurs between them. To avoid this, only one slave reader transmits a signal in an arbitrary time slot. In this case, the time slot for the self operation is set in advance. In the present embodiment, each slave leader operates in the order of lane numbers for convenience.

Returning to FIG. 3, in step S10, the master / slave reader operates as a master leader at a predetermined time period to transmit a wake-up signal. In response to the wake-up signal, in step S12 to step S18, as well as other slaves, the master / slave reader is operated. The readers are synchronized in time, and all the tags of the vehicle located at a distance from which they can receive will also wake up from sleep. This wake-up signal may be sent continuously, for example by 0.8 seconds. Thereafter, the master / slave reader operates as a slave device until the next wake-up signal is transmitted (step S20).

In this way, in the state where all slave readers and tags are all woken up, each slave reader judges whether its operation sequence has been reached in the standby state (step S21) (step S22), and if so, proceeds to step S24. The command signal is sent toward the tag, and in step S26, an RF response signal is received from the tag. The time required for such an operation is about 100 ms. Next, in step S30, it is determined whether the RF response signal received from the tag is an RF response signal from the vehicle entering the lane. If it is correct, the process proceeds to step S32, where the identification information is extracted and stored, otherwise it is not. In step S34, this is ignored.

In the above configuration, when the communication of the slave leader 1 ends, communication of the slave leader 2 is immediately started, and then communication of the slave leader 3 is started. However, when the number of lanes increases, the number of slave readers increases, and thus, the time required for all slave leaders to operate once (Inventory Round Time) may also increase, thereby preventing the recognition of an entry vehicle. In view of this, the slave reader at a distance that the radio wave transmitted by one slave reader does not affect, and in this embodiment, the slave reader 4 can send a command signal simultaneously with the slave reader and the slave reader 1 in this embodiment. This reduces the time required for all slave leaders to operate once.

On the other hand, since the wake-up signal sent by the master / slave reader must reach all slave readers and tags, it is desirable to make the intensity of the output larger than that of the command signal.

5 is a detailed functional block diagram of an apparatus for determining a lane of entry of a vehicle using RFID according to the present invention. As shown in FIG. 5, the apparatus for determining the lane of entry of a vehicle using RFID according to the present invention is installed in pairs at predetermined intervals in each lane of a toll gate or a port entrance and exit of a toll road for RF transmission / reception and phase detection. Two reader antennas 100 and 102, each functioning, modulate a wake-up signal or a command signal and output the RF signals through the reader antenna 100 for RF transmission / reception. The RF processor 140 demodulating the RF response signal received through the reception reader antenna 100, and the power of the RF response signal received through the RF transmission / reception reader antenna 100 and the RF processor 140 and will be described later. It is installed at the rear end of the power divider (Power Divider) and the RF antenna for transmitting / receiving to the phase difference detector (160), and the RF antenna for transmitting / receiving the reader antenna (100) or the RF processing unit. Shear RF switch 110, shear RF switch to alternatively connect to (140) side Interposed between the 110 and the RF processor 140, the RF switch 140 is connected to the front end RF switch, i.e., an RF transmitter / receiver reader antenna 100 or a power splitter 120. 130, the level of the RF response signal received through the phase detection reader antenna 102 is the same as the level of the RF response signal input through the power divider 120, that is, the RF transmission / reception reader antenna 100. A phase difference detector 160 and a front end RF switch 110 for detecting a phase difference between the RF response signal input through the attenuator 150, the power divider 120, and the RF response signal input through the attenuator 150. The overall operation of the RFID reader such as the switching timing of the rear RF switch 130 is collectively controlled, and the RF response signal currently input by the phase difference information input from the phase difference detector 160 is transmitted from the vehicle entering the lane. Become If it is sent from a vehicle entering its lane after checking whether the vehicle is sent from a vehicle entering another lane, a reader controller for extracting tag identification information from an RF response signal input after being demodulated through the RF processor 140 ( 170).

In the above configuration, a directional coupler may be used instead of the power divider 120. Furthermore, instead of removing the attenuator 150, the signal level between the two may be equalized by interposing the amplifier 180 as shown by the dotted line between the power divider 120 and the phase difference detector 160. Furthermore, the phase difference information output from the phase difference detector 160 directly outputs a voltage signal corresponding to the phase difference or compares the reference phase difference signal shown by the dotted line provided by the reader controller 170 with the phase difference between them in a more intelligent form. The RF response signal of the own lane or the other lane may be determined according to the result, and the determination result may be transmitted to the reader controller 170. In the following claims, the output signal of the phase difference detector is referred to as a 'lane identification signal'. The reader controller 170 may be implemented as a microcontroller, and the front RF switch and the rear RF switch may be implemented as electronic switches.

Hereinafter, the operation of the apparatus for determining the lane of entry of the vehicle using the RFID of the present invention having the above-described configuration will be described.

When the RFID reader is an RFID reader that performs dual functions of the master and the slave, first, the front RF switch 110 is switched to the rear RF switch 130 and the rear RF switch 130 is transferred to the RF processor 140. In the switched state, the wake-up signal modulated by the RF processor 140 is transmitted through the RF transmission / reception reader antenna 100. Even when operating as a slave RFID reader, the command signal modulated through the RF processor 140 is transmitted toward the tag in the switched state as described above, and the output strength of the wake-up signal is greater than the output strength of the command signal. It is desirable to.

On the other hand, at the timing of receiving the RF response signal from the tag, both the front and rear RF switches 110 and 130 are switched to the power divider 120 side. As a result, the RF response signal received through the RF transmitting / receiving reader antenna 100 is distributed through the power divider 120 and preferably divided into 1/2, and then the RF processor 140 and the phase difference detector ( 160). At the same time, the RF response signal received through the phase detection reader antenna 102 is attenuated by the attenuator 150 such that its level is equal to the power level of the RF response signal passed through the power divider 120. 160).

Subsequently, the phase difference detector 160 detects the phase difference between the two RF response signals and then converts the voltage into a voltage or outputs a result of comparing the detected phase difference with the reference phase difference to the reader controller 170.

Finally, the reader controller 170 checks the phase difference information output from the phase difference detector 160 to determine whether the corresponding RF response signal is transmitted from the vehicle entering the lane or from the vehicle entering the other lane. If it is later sent from a vehicle of another lane, it is ignored, whereas if it is sent from a vehicle of its own lane, the identification information is extracted and stored.

The apparatus and method for determining a lane of entry of a vehicle using RFID according to the present invention can be implemented in various ways within the scope of the technical idea of the present invention without being limited to the above-described embodiment.

1 is a view for explaining the principle of discriminating the entry lane of a vehicle using a conventional RFID;

2 is a view for explaining the principle of the phase interference method used in the apparatus and method for determining the lane of entry using the RFID of the present invention;

3 is a flowchart illustrating a method for determining an entry lane of a vehicle using RFID according to the present invention;

4 is a view for explaining a method of determining the communication order of each RFID reader in the apparatus and method for determining the vehicle lane using the RFID of the present invention;

5 is a detailed functional block diagram of an apparatus for determining a lane of entry of a vehicle using RFID according to the present invention.

*** Explanation of symbols for the main parts of the drawing ***

100, 102: reader antenna, 110, 130: RF switch,

120: power divider, 140: RF processing unit,

150: attenuator, 160: phase difference detector,

170: reader control unit, 180: amplifier

Claims (13)

Two reader antennas installed in pairs at predetermined intervals in each lane of a toll gate or a port access road of a toll road and functioning for RF transmission / reception and phase detection respectively; Modulates a wake-up signal or a command signal and outputs it through the RF transmitting / receiving reader antenna, and receives it through the RF transmitting / receiving reader antenna after being transmitted from a tag attached to an entering vehicle or container. An RF processor for demodulating the received RF response signal; A phase difference detector for detecting a phase difference between the RF response signal received through the RF transmission / reception reader antenna and the phase detection reader antenna, respectively, and outputting a lane identification signal; Distribution means for distributing and transmitting the RF response signal received from the RF transmitting / receiving reader antenna to the RF processing unit and the phase difference detector; Switching means for alternatively connecting the RF transmitting / receiving reader antenna to the distribution means and the RF processor; A reader which extracts and processes tag identification information from the RF response signal when the RF response signal currently input by the lane identification signal is transmitted from the vehicle of its lane and then is determined from the vehicle of the lane; An apparatus for determining a lane of entry of a vehicle using RFID including a control unit. The method of claim 1, The switching means consists of a front end RF switch and a rear end RF switch, The front end RF switch alternatively connects the RF transmitting / receiving reader antenna to the rear end RF switch and distribution means, The rear end RF switch is connected to the RF processing unit and the front end RF switch and the distribution means, characterized in that the vehicle access lane determination device using RFID. The method of claim 2, And the distribution means is a power divider or a directional coupler. The method of claim 2, The rear end of the phase detection reader antenna further includes an attenuator for matching the level of the received RF response signal with the level of the RF response signal output from the distribution means. Lane determination device. The method of claim 2, The rear end of the distribution means is further provided with an amplifier for adjusting the level of the RF response signal output therefrom to be equal to the level of the RF response signal received from the phase detection reader antenna. Device for determining lane of entry. The method of claim 2, wherein the lane identification signal is the phase difference signal, The reader controller determines whether the RF response signal currently input is transmitted from a vehicle or a container in a lane according to a result of comparing the phase difference signal with a reference phase difference signal. Lane determination device. The method of claim 2, wherein the phase difference detector compares the phase difference signal with a reference phase difference signal provided from the reader controller to determine whether the RF response signal currently input is transmitted from a vehicle in its lane. Apparatus for determining the lane of entry using the RFID, characterized in that for providing the lane identification signal. 8. The phase difference detector according to claim 6 or 7, wherein the phase difference detector

Where ? Represents the phase difference, D represents the distance between the RF transmitting / receiving reader antenna and the phase detecting reader antenna, λ represents the wavelength of the incident wave, and θ represents the incident wave. An apparatus for determining a lane of entry of a vehicle using RFID, wherein the incident angle is indicated. Lanes to which vehicles are entered by a RFID reader equipped with two reader antennas, which are installed in pairs at predetermined intervals in each lane of a toll gate or a port entrance to a toll road, and each function for RF transmission / reception and phase detection. , But The RF inputted according to a result of comparing a phase difference of an RF response signal transmitted from an active tag attached to a vehicle or a container through the RF transmission / reception reader antenna and the phase detection reader antenna, respectively, with a reference phase difference A method for determining a lane of entry of a vehicle using RFID for determining whether a response signal is transmitted from a vehicle in a lane. The method of claim 9,

Where ? Represents the phase difference, D represents the distance between the RF transmitting / receiving reader antenna and the phase detecting reader antenna, λ represents the wavelength of the incident wave, and θ represents the incident wave. A method for discriminating an entry lane of a vehicle using RFID, wherein the incident angle is indicated. The method of claim 10, In the state of two or more RFID readers, one of them has a function as a master reader and a slave reader, When functioning as the master leader, it sends out a wake-up signal to all slave readers and tags, and then acts as a slave leader. And the slave readers transmit command signals in a predetermined order while being synchronized by the wake-up signal. The method of claim 11, And the intensity of the output of the wake-up signal is greater than the intensity of the output of the command signal. The method of claim 11, And the slave reader outputs the command signal simultaneously with other slave readers within a range in which the output of the command signal does not interfere with other slave readers.

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