KR20120089178A - Rfid tag and rfid reader, and method for tracking location using the same - Google Patents

Abstract

PURPOSE: An RFID tag, an RFID reader, and a position tracking method using the same are provided to reduce the size and weight of the RFID tag by not performing a self-position calculation process. CONSTITUTION: A GPS receiver receives a GPS satellite signal from a plurality of satellites(300a,300b,300c,300d). An RFID reader(200) calculates the reception time information of each GPS satellite signal. The position of an RFID tag(100a,100b) is calculated by using each GPS satellite signal. A baseband signal processing unit generates a transmission frame. The transmission frame includes the reception time information and an identifier of the RFID tag. A transmission unit transmits a transmission frame.

Description

RDF tag and RDF reader and location tracking method using same {RFID TAG AND RFID READER, AND METHOD FOR TRACKING LOCATION USING THE SAME}

The present invention relates to an RFID tag and an RFID reader and a location tracking method using the same.

Recently, as RFID (Radio Frequency Identification) technology is applied in various fields, RFID technology has been used for location tracking technology.

After requesting an RFID tag to an object, the tag signal emitted from the RFID tag is received by three or more RFID readers, and the position of the RFID tag is measured by triangulation using the signal strength or the arrival time of the signals received from the three or more readers. do. However, since the location tracking method needs to recognize the tag signal of the RFID tag in three or more readers for the location tracking of one RFID tag, it requires a large number of readers when used in a large area outdoors. In addition, the RFID tag must exist within a certain area formed by connecting three or more readers so that more than three readers can receive the tag signal of the tag to track the location of the RFID tag. It becomes impossible to trace.

In order to solve this problem, an RFID tag for receiving a GPS (Global Positioning System) satellite signal and calculating its position has been proposed. That is, by receiving a GPS satellite signal from the RFID tag, calculate its position and transmit coordinate information about the calculated position to the tag signal, so that even if the reader receives the tag signal from one of the readers of the RFID tag Location tracking becomes possible. Such a location tracking method has an advantage of identifying the location of the RFID tag even when the RFID tag is out of a certain area formed by three or more readers. However, since the location calculation must be performed on the RFID tag, power consumption is greatly increased. . In particular, since power consumption in a battery-based RFID tag is directly related to the life of the RFID tag, an increase in power consumption shortens the life of the RFID tag. In addition, since the module for calculating the position of the RFID tag must be mounted, the cost of the RFID tag can be increased, and the weight and size of the RFID tag can be difficult.

The technical problem to be solved by the present invention is to provide an RFID tag, an RFID reader, and a location tracking method using the same, which can reduce the unit cost and power consumption of the RFID tag used for location tracking, and realize the lightweight and miniaturized RFID tag. .

The present invention also provides an RFID tag, an RFID reader, and a location tracking method using the same, which can realize a small amount of the RFID reader used for location tracking.

According to one embodiment of the invention, an RFID tag is provided that communicates with an RFID reader. The RFID tag includes a GPS receiver, a baseband signal processor, and a transmitter. The GPS receiver receives GPS (Global Positioning System) satellite signals from a plurality of satellites, respectively, and calculates reception time information of each GPS satellite signal necessary for calculating the position of the RFID tag in the RFID reader. The baseband signal processor generates a transmission frame including reception time information of each GPS satellite signal and an identifier of the RFID tag. The transmitter transmits the transmission frame.

The GPS receiver may generate the same C / A code as the Coarse Acqusition (C / A) code of each GPS satellite signal and calculate the reception time information of each GPS satellite signal through correlation of the two C / A codes. have.

The GPS receiver may calculate a correlation value by correlating two C / A codes by shifting the C / A codes of the GPS receiver by one chip in response to a C / A code counter. In this case, the value of the C / A code counter that maximizes the correlation value may be used as the reception time information of the GPS satellite signal.

The transmission frame may include an identifier field including an identifier of the RFID tag, and a payload field including data. In this case, the baseband signal processor may include the reception time information of each GPS satellite signal in the payload field.

The baseband signal processor may further include an identifier of a satellite that transmits the GPS satellite signals in the payload field.

The transmission frame may include a serial number field including a serial number of the RFID tag, and a response data field including response data in response to a command signal from the RFID reader. In this case, the baseband signal processor may include the reception time information of each GPS satellite signal in the response data field.

The GPS receiver may calculate reception time information of at least four GPS satellite signals for receiving a Global Positioning System (GPS) satellite signal with at least four satellites.

According to another embodiment of the present invention, an RFID reader for communicating with an RFID tag is provided. The RFID reader includes a GPS receiver, a tag receiver, and a position calculator. The GPS receiver receives a GPS (Global Positioning System) satellite signal from a plurality of satellites and extracts the satellite information. The tag receiving unit receives a transmission frame from the RFID tag and extracts reception time information of a GPS (Global Positioning System) satellite signal received from the plurality of satellites in the RFID tag from the transmission frame. The position calculator calculates the position of the RFID tag using information of each satellite and reception time information of each GPS satellite signal.

The transmission frame may include an identifier field including an identifier of the RFID tag, and a payload field including data. In this case, the tag receiver may extract the reception time information of each GPS satellite signal from the payload field.

The transmission frame may include a serial number field including an identifier of the RFID tag, and a response data field including response data in response to a command signal from the RFID reader. In this case, the tag receiver may extract the reception time information of each GPS satellite signal from the response data field.

According to another embodiment of the present invention, a method for tracking the location of the RFID tag in a location tracking system including an RFID tag, an RFID reader in communication with the RFID tag. The location tracking method may include receiving, at the RFID reader, reception time information of a GPS satellite signal received by the RFID tag from a plurality of satellites, from the RFID tag, and receiving, at the RFID reader, a GPS satellite signal from the plurality of satellites. Receiving and extracting the information of the satellite, and in the RFID reader, calculating the position of the RFID tag using the reception time information of each GPS satellite signal and the information of the satellite.

According to an embodiment of the present invention, since it is not necessary to perform a magnetic position calculation by receiving a GPS signal from the RFID tag, the RFID tag can be made smaller, lighter and cheaper, and the power consumption of the RFID tag can be reduced, so that Can increase lifespan.

In addition, the RFID reader capable of receiving GPS signals calculates the position of the RFID tag through communication between the GPS signal and the RFID tag, so that at least three readers recognize the RFID tag to track the position of the RFID tag. Can be reduced.

1 is a view showing a location tracking system according to an embodiment of the present invention.
2 is a diagram illustrating an example of an RFID tag illustrated in FIG. 1.
3 is a diagram illustrating another example of the RFID tag illustrated in FIG. 1.
4 is a diagram illustrating an example of the RFID reader shown in FIG. 1.
5 is a flowchart illustrating a method of calculating reception time information of a GPS satellite signal in an RFID tag according to an embodiment of the present invention.
FIG. 6 is a diagram illustrating an example of calculating reception time information of a GPS satellite signal illustrated in FIG. 5.
7 to 9 are diagrams illustrating a transmission frame structure according to an embodiment of the present invention, respectively.
10 is a flowchart illustrating a location tracking method of a location tracking system according to an exemplary embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification and claims, when a section is referred to as "including " an element, it is understood that it does not exclude other elements, but may include other elements, unless specifically stated otherwise.

Now, an RFID tag, an RFID reader, and a location tracking method using the same according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing a location tracking system according to an embodiment of the present invention.

Referring to FIG. 1, a location tracking system includes an RFID reader 200 and at least four satellites, for example, satellites, that communicate with at least one RFID tag 100a, 100b and at least one RFID tag 100a, 100b. (300a, 300b, 300c, 300d).

At least one RFID tag (100a, 100b) is a GPS satellite signal received from a plurality of satellites (300a, 300b, 300c, 300d) from the received GPS satellite signal from the RFID reader 200 of the RFID tag (100a, 100b) Calculate the reception time information of the GPS satellite signal needed to calculate the position, and identify the identifier of the satellites 300a, 300b, 300c, and 300d that transmitted the GPS satellite signal, the reception time information of the GPS satellite signal, and the RFID tag ( The tag signal including the tag information of 100a and 100b is transmitted. The tag information may include identifiers and status information of the RFID tags 100a and 100b. The GPS satellite signal includes satellite information, that is, time information when the GPS satellite signal is transmitted, and orbital information indicating the position of the satellite at that time, almanac, ephemeris, and correction information for error correction.

The RFID tag 100 receives the identifier and the reception time of the satellites 300a, 300b, 300c, and 300d in the tag signal only when the reception time information is obtained from the GPS satellite signals of at least four satellites 300a, 300b, 300c, and 300d. Including information can be transmitted.

The RFID tag 100 may be a unidirectional tag that periodically transmits a tag signal to the RFID reader 200. For example, the RFID tag 100 may be a unidirectional active tag in the 2.45 GHz band that conforms to the ISO / IEC 24730-2 standard.

In addition, the RFID tag 100 may be a bidirectional tag that may periodically transmit a tag signal to the RFID reader 200 and receive a wake up signal and other command signals transmitted from the RFID reader 200. For example, it may be a bidirectional active tag in the 433 MHz band conforming to the ISO / IEC 18000-7 standard.

The RFID reader 200 receives a tag signal from at least one RFID tag 100a or 100b within its communication radius, and extracts received time information and tag information of the GPS satellite signal from the tag signal.

In addition, the RFID reader 200 receives GPS satellite signals from the plurality of satellites 300a, 300b, 300c, and 300d, and track information and correction information of the satellites 300a, 300b, 300c, and 300d from the received GPS satellite signals. Collect it.

The RFID reader 200 calculates the positions of the RFID tags 100a and 100b by using the reception time information of the GPS satellite signal of the RFID tag 100, the orbit information and the correction information of the collected satellite 300a, and thereby, the RFID tag. Track the position of (100a, 100b).

As such, when the RFID tags 100a and 100b receive the GPS satellite signals from the satellites 300a, 300b, 300c, and 300d, the RFID tags 100a and 100b do not calculate their position by using the GPS satellite signals, and receive time information of the GPS satellite signals. By calculating only and transmitting to the RFID reader 200, it is possible to reduce the power consumption according to the magnetic position calculation.

2 is a diagram illustrating an example of an RFID tag illustrated in FIG. 1.

The RFID tag 100 illustrated in FIG. 2 may be at least one of the RFID tags 100a and 100b illustrated in FIG. 1 as an example of the unidirectional tag.

Referring to FIG. 2, the RFID tag 100 includes a reception antenna 110, a GPS receiver 120, a baseband signal processor 130, and a transmitter 140.

The receiving antenna 110 receives GPS satellite signals from at least four satellites 300a, 300b, 300c, and 300d.

The GPS receiver 120 demodulates the received GPS satellite signal to calculate the reception time of the GPS satellite signal, and transmits the reception time information of the GPS satellite signal to the baseband signal processor 130.

The baseband signal processor 130 generates a transmission frame including the reception time information and the tag information of the GPS satellite signal, generates a tag signal by modulating the transmission frame, and transmits it to the transmitter 140.

The tag signal may be transmitted to the RFID reader 200 through the transmitter 140 at a predetermined cycle. The baseband signal processor 130 may generate a transmission frame including only tag information when GPS satellite signals from at least four satellites 300a, 300b, 300c, and 300d are not received in a corresponding period. The transmitter 140 loads a tag signal on a carrier frequency and transmits the tag signal through a transmission antenna (not shown).

3 is a diagram illustrating another example of the RFID tag illustrated in FIG. 1.

The RFID tag 100 illustrated in FIG. 3 may be at least one of the RFID tags 100a and 100b illustrated in FIG. 1 as an example of the bidirectional tag.

Referring to FIG. 3, the RFID tag 100 ′ is the same as the RFID tag 100 of FIG. 3 except that the RFID tag 100 ′ further includes a reader receiver 150.

The reader receiver 150 receives a wakeup signal and other command signals from the RFID reader 200, and transmits the received wakeup signal and other command signals to the baseband signal processor 130.

When the baseband signal processor 130 receives the wakeup signal, the baseband signal processor 130 activates the RFID tag 100 ′ to enable communication with the RFID reader 200. In addition, when the baseband signal processor 130 receives other command signals, the baseband signal processor 130 transmits the response data to the RFID reader 200 through the transmitter 140.

4 is a diagram illustrating an example of the RFID reader shown in FIG. 1.

Referring to FIG. 4, the RFID reader 200 includes a reception antenna 210, a GPS receiver 220, a tag receiver 230, and a position calculator 240. In addition, the RFID reader 200 may further include a transmitter 250.

The receiving antenna 210 receives GPS satellite signals from the plurality of satellites 300a, 300b, 300c, and 300d.

The GPS receiver 220 demodulates the received GPS satellite signal, extracts satellite information, and transmits the extracted satellite information to the position calculator 240.

The tag receiving unit 230 receives a tag signal from the RFID tags 100a and 100b, demodulates the tag signal, and extracts the reception time information of the GPS satellite signal and the identifier and tag information of the satellite transmitting the GPS satellite signal. The extracted information is transmitted to the position calculator 240.

The position calculator 240 calculates the positions of the RFID tags 100a and 100b by using the reception time information of the GPS satellite signal received from the tag receiver 230 and the satellite information corresponding to the satellite identifier.

 The transmitter 250 may transmit the wakeup signal and other command signals to the RFID tags 100a and 100b.

Next, a method of calculating reception time information of the GPS satellite signal by the GPS receiver 110 of the RFID tag 100 will be described with reference to FIGS. 5 and 6.

5 is a flowchart illustrating a method of calculating reception time information of a GPS satellite signal in an RFID tag according to an embodiment of the present invention, and FIG. 6 is an example of calculating reception time information of a GPS satellite signal shown in FIG. 5. The figure shown.

First, referring to FIG. 6, in the GPS satellite signal, bit data corresponding to satellite information is spread from a satellite 300a into a coarse acqusition (C / A) code and transmitted at a time t1. The C / A code is a repeating 1 MHz pseudo random noise (PRN) code. Each satellite has a different C / A code.

The GPS receiver 110 generates a C / A code such as a C / A code of the satellite 300a at the same time as the time t1 of transmitting the GPS satellite signal from the satellite 300a. Meanwhile, the GPS receiver 110 may not generate a C / A code at the same time as the satellite 300a in the GPS receiver 110 due to an internal clock error C _B.

Since the GPS satellite signal of the satellite 300a will be delayed by the distance coming from the satellite 300a to the GPS receiver 110, the GPS receiver 110 is the C / A code of the satellite 300a and the C of the GPS receiver 110. It is possible to calculate the reception time of the GPS satellite signal transmitted from the satellite 300a through autocorrelation of the / A code.

Specifically, referring to FIGS. 5 and 6, when the GPS satellite signal is transmitted from the satellite 300a, the GPS receiver 110 may detect the satellite at the same time t1 as the time when the GPS satellite signal is transmitted from the satellite 300a. The C / A code of the GPS receiver 110, such as the C / A code of 300a, is generated (S510), and the C / A code of the GPS receiver 110 is shifted by one chip in response to the C / A code counter (S510). S520). In this case, the time for shifting the C / A code by one chip is one millionth of a second, which is the same time as the time for transmitting one chip of the C / A code of the satellite 300a.

Next, when the GPS satellite signal received by the GPS receiver 110 is delayed by the distance from the satellite 300a to the GPS receiver 110 in the satellite 300a (S530), the delayed GPS satellite signal is demodulated. / A code is extracted (S540).

When the C / A code of the satellite 300a is extracted, the GPS receiver 110 autonomously correlates the C / A code of the GPS receiver 110 with the C / A code of the satellite 300a to calculate an autocorrelation value ( S550).

The GPS receiver 110 continuously shifts the C / A code of the GPS receiver 110 by one chip and continues to autocorrelate with the C / A code of the GPS receiver 110 and the C / A code of the satellite 300a. Calculate

)을 계산한다(S560). 수신 시각(

)은 인공위성(300a)에서 GPS 수신부(110)까지의 거리에 따른 GPS 위성 신호의 지연 시간을 의미할 수 있다. When the C / A code of the GPS receiver 110 and the C / A code of the GPS receiver 110 coincide with each other, the autocorrelation value is maximized. Therefore, the GPS receiver 110 is connected to the C / A code of the GPS receiver 110. The reception time of the GPS satellite signal from the value of the C / A code counter at which the autocorrelation value of the C / A code of the satellite 300a is maximized (

) Is calculated (S560). Receive time (

) May mean a delay time of the GPS satellite signal according to the distance from the satellite 300a to the GPS receiver 110.

The GPS receiver 110 may use a C / A code counter value in which the autocorrelation value of the C / A code of the GPS receiver 110 and the C / A code of the satellite is maximum as reception time information of the GPS satellite signal.

On the other hand, when there is a clock error (C _B ) in the GPS receiver 110, the RFID reader 200 uses a C / A code counter value that maximizes the autocorrelation between the C / A code and the satellite C / A code. The RFID tag, for example, may be received from an RFID tag (100a of FIG. 1) to compensate for a clock error C _B and calculate a position of the RFID tag 100a.

The method of calculating the position of the RFID tag 100a in the RFID reader 200 will be briefly described as follows.

In order to obtain three unknowns corresponding to the (x, y, z) coordinates, only three reception time information of the GPS satellite signal can be used to calculate the position. However, since the offset due to the clock error C _B is included in the reception time information, the position error is large due to the inaccuracy of the reception time information. Therefore, in order to compensate for the clock error C _B , additional reception time information of one satellite satellite signal is required.

That is, the RFID reader 200 compensates the clock error C _B by obtaining four unknowns corresponding to (x, y, z, C _B ) from at least four received time information received from the RFID tag 100a. To calculate a more accurate position of the RFID tag 100a. 7 is a diagram illustrating an example of a transport frame structure according to an embodiment of the present invention.

The transmission frame shown in FIG. 7 is a message frame of 152 bits in the ISO / IEC 24730-2-1 standard, which is used by an RFID tag to periodically transmit tag information to an RFID reader.

Referring to FIG. 7, the transmission frame includes a preamble field, a transmitter status field, a transmitter identifier field, a payload field, and a CRC field.

The preamble field is a field indicating the start of a transmission frame and may be composed of 8 bits.

The transmitter status field includes the status of the RFID tag and may consist of 4 bits.

The transmitter identifier field includes an identifier of an RFID tag and may be 32 bits.

The payload field is a data field and may be 96 bits.

According to an embodiment of the present invention, the payload field of this frame is used to transmit the satellite identifier and the reception time information of the GPS signal received from the satellite to the RFID reader 200.

That is, the payload field includes a satellite identifier and reception time information of a GPS signal received from the satellite. At this time, the baseband signal processing unit 120 is a total of four satellite identifiers (SID_1 ~ SID_4) and corresponding to the payload field of one transmission frame so that the position of the RFID tag 100 can be calculated by the RFID reader 200. It receives and transmits the reception time information (C / A_1 to C / A_4) of GPS satellite signals received from four satellites. The satellite identifiers SID_1 to SID_4 may be 5 bits to identify 32 satellites. The reception time information of the GPS satellite signal may be a 19-bit C / A counter value.

The CRC field is the last field of the transmission frame and includes error detection information.

8 is a diagram illustrating another example of a transport frame structure according to an embodiment of the present invention.

The transmission frame shown in FIG. 8 is a message frame of 164 bits in the ISO / IEC 24730-2-2 standard. As in FIG. 7, the RFID reader 200 receives received time information of the satellite identifier and the GPS signal received from the satellite. The payload field of this frame is used for transmission in.

Referring to FIG. 8, the transmission frame has the same structure as the transmission frame of FIG. 7 except that the transmission frame further includes a sub-blink field.

The sub-blink field includes information on the number of times of the corresponding sub-blink when transmitting up to eight sub-links. In the ISO / IEC 24730-2-2 standard, an RFID tag carries desired information on a blink signal and transmits it.

9 is a view showing another example of a transport frame structure according to an embodiment of the present invention.

The transmission frame shown in FIG. 9 is a response message frame transmitted from an RFID tag in the ISO / IEC 18000-7 standard to an RFID reader, and the response message frame is used for the RFID tag to respond to a command signal from the RFID reader. .

Referring to FIG. 9, a transmission frame includes a protocol code field, a tag status field, a packet length field, a session identifier field, a manufacturer field, a serial number field, a command code field, a response data field, and a CRC field.

The protocol code field contains a protocol identifier indicating which standard is currently in compliance. For example, the protocol identifier 0x31 may represent 18000-7 version 0 and the protocol identifier 0x40 may represent 18000-7 version 1. The tag status field includes information representing various states of the RFID 100 and may be 2 bytes. For example, the tag status field may include information such as a tag type, a hardware fault, and the like. The packet length field includes length information of a transport frame and may consist of 2 bytes.

The session identifier field includes identifier information of a specific session and may consist of 2 bytes.

The manufacturer field includes identifier information assigned to the manufacturer of the RFID tag 100 and may be 2 bytes.

The serial number field includes the serial number of the RFID tag 100 and may be 4 bytes. The serial number of the RFID tag 100 may be an identifier of the RFID tag 100.

The command code field may include command code information corresponding to a command signal from an interrogator, that is, the RFID reader 200, and may include 1 byte.

The response data field includes response data corresponding to the command signal from the RFID reader 200 and may be configured as (N + 5) bytes. According to an embodiment of the present invention, the response data field of the frame is used to transmit at least four satellite identifiers and the reception time information of the GPS satellite signal received from the satellite to the RFID reader 200.

The response data field includes a universal data block (UDB) type field, a UDB length field, a request offset field, and a UDB data field, and includes four satellite identifiers (SID_1 to SID_4) and corresponding four in the UDB data field. The reception time information C / A_1 to C / A_4 of the GPS satellite signal received from the satellite may be included.

Finally, the CRC field is the last field of the transmission frame and includes error detection information.

10 is a flowchart illustrating a location tracking method of a location tracking system according to an exemplary embodiment of the present invention.

10 illustrates an example of a method for tracking a location of the RFID 100a based on the location tracking system of FIG. 1.

Referring to FIG. 10, when the RFID 100a receives a GPS satellite signal from at least four satellites 300a, 300b, 300c, and 300d (S1010), the RFID 100a receives the GPS satellite signals of the satellites 300a, 300b, 300c, and 300d. The reception time is calculated (S1020).

The RFID 100a generates a transmission frame including the reception time information of the four GPS satellite signals, the identifiers of the satellites 300a, 300b, 300c, and 300d transmitting the corresponding GPS satellite signals and their own tag information (S1030). The tag signal modulated with the transmission frame is transmitted (S1040).

The RFID reader 200 receives a GPS satellite signal from at least one satellite of the satellites 300a, 300b, 300c, and 300d (S1050).

In addition, the RFID reader 200 receives a tag signal from the RFID tag 100a within its communication radius (S1060), and satellites that transmit the received time information of the four GPS satellite signals and the corresponding GPS satellite signals from the tag signal. Identifier and its own tag information is extracted (S1070).

The RFID reader 200 collects orbit information and correction information of the satellites 300a, 300b, 300c, and 300d from the GPS satellite signals received from the satellites 300a, 300b, 300c, and 300d (S1080). The position of the RFID tag 100a is calculated using the reception time information of four GPS satellite signals extracted from the tag signal of 100a) (S1090).

An embodiment of the present invention is not implemented only through the above-described apparatus and / or method, but may be implemented through a program for realizing a function corresponding to the configuration of the embodiment of the present invention or a recording medium on which the program is recorded. Such an implementation can be easily implemented by those skilled in the art to which the present invention pertains based on the description of the above-described embodiments.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

Claims (18)

In an RFID tag that communicates with an RFID reader,
A GPS receiver for receiving GPS (Global Positioning System) satellite signals from a plurality of satellites, respectively, and calculating reception time information of each GPS satellite signal necessary for calculating the position of the RFID tag in the RFID reader;
A baseband signal processor for generating a transmission frame including reception time information of each GPS satellite signal and an identifier of the RFID tag, and
Transmitter for transmitting the transmission frame
RFID tag comprising a. In claim 1,
The GPS receiver,
And generating a C / A code identical to a C / A (Coarse Acqusition) code of each GPS satellite signal and calculating received time information of each GPS satellite signal through correlation of two C / A codes. In claim 2,
The GPS receiver,
The C / A code of the GPS receiver is shifted by one chip in response to the C / A code counter to correlate two C / A codes to calculate a correlation value,
And a value of a C / A code counter at which the correlation value is maximum is used as reception time information of a corresponding GPS satellite signal. In claim 1,
The transmission frame,
An identifier field containing an identifier of the RFID tag, and
Includes a payload field that contains data,
And the baseband signal processor includes reception time information of each GPS satellite signal in the payload field. 5. The method of claim 4,
And the baseband signal processing unit further includes an identifier of a satellite transmitting the GPS satellite signals in the payload field. 5. The method of claim 4,
The RFID frame is transmitted periodically. 5. The method of claim 4,
The transmission frame,
Subblink field including information on the number of times corresponding subblink
RFID tag further comprising. In claim 1,
The transmission frame,
A serial number field including a serial number of the RFID tag, and
A response data field containing response data in response to a command signal from the RFID reader,
And the baseband signal processor includes reception time information of each GPS satellite signal in the response data field. 9. The method of claim 8,
And the baseband signal processing unit further includes an identifier of a satellite transmitting the GPS satellite signals in the response data field. In claim 1,
The GPS receiver,
An RFID tag that calculates reception time information for at least four GPS satellite signals that receive GPS (Global Positioning System) satellite signals with at least four satellites. In an RFID reader that communicates with an RFID tag,
A GPS receiver for receiving a GPS (Global Positioning System) satellite signal from a plurality of satellites and extracting information of the satellites;
A tag receiver configured to receive a transmission frame from the RFID tag and extract reception time information of a GPS (Global Positioning System) satellite signal received from the plurality of satellites in the RFID tag from the transmission frame; and
Position calculation unit for calculating the position of the RFID tag using the information of each satellite and the reception time information of each GPS satellite signal
RFID reader comprising a. In claim 11,
The transmission frame,
An identifier field containing an identifier of the RFID tag, and
Include a payload field containing data,
And the tag receiver extracts reception time information of each GPS satellite signal from the payload field. The method of claim 12,
The transmission frame,
Subblink field including information on the number of times corresponding subblink
RFID reader further comprising. In claim 11,
The transmission frame,
A serial number field containing an identifier of the RFID tag, and
A response data field containing response data in response to a command signal from the RFID reader,
And the tag receiver extracts reception time information of each GPS satellite signal from the response data field. In the method for tracking the position of the RFID tag in a location tracking system comprising an RFID tag, an RFID reader in communication with the RFID tag,
Receiving, at the RFID reader, reception time information of a GPS satellite signal received by the RFID tag from a plurality of satellites, from the RFID tag;
Receiving, at the RFID reader, GPS satellite signals from the plurality of satellites and extracting information of the satellites; and
Calculating, by the RFID reader, the position of the RFID tag using reception time information of each GPS satellite signal and information of the corresponding satellite;
Location tracking method comprising a. 16. The method of claim 15,
Wherein the receiving comprises:
Receiving a transmission frame including reception time information of each GPS satellite signal from the RFID tag, and
And extracting reception time information of the GPS satellite signal from a payload field including data in the transmission frame. 16. The method of claim 15,
Wherein the receiving comprises:
Receiving a transmission frame including reception time information of each GPS satellite signal from the RFID tag, and
Extracting received time information of each GPS satellite signal from a response data field including response data responsive to a command signal from the RFID reader in the transmission frame. 16. The method of claim 15,
Receiving, at the RFID tag, the GPS satellite signals from the plurality of satellites,
Extracting a Coarse Acqusition (C / A) code of each GPS satellite signal from the RFID tag, and
Generating the same C / A code as the C / A code of each GPS satellite signal and calculating reception time information of each GPS satellite signal through correlation of two C / A codes
Location tracking method further comprising.

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