KR20100096766A - Active rfid tag and tracing method thereof - Google Patents

Abstract

PURPOSE: An active wireless frequency recognition tag and a location searching method of the same are provided to transmit the sub blink ID information corresponding to the sequence of the sub blink with the sub blink when an active tag transmits the sub blink in a RTLS(Real Time Locating Systems) system, thereby easily performing location calculation by serial arrangement of sub blinks without comparing arrival time information of the sub blink one by one in location processor engine. CONSTITUTION: A location processor engine stores ID information of tag which sent a blink signal, sub blink ID information, and arrival time information of each sub blink(S402). The engine again groups information grouped per tag ID according to each sub blink ID(S404). If the arranged sub blinks are more than three, the engine calculates the location of active tag through the arrival time information of the sub blinks(S406,S408).

Description

Active RFID tag and location tracking method {ACTIVE RFID TAG AND TRACING METHOD THEREOF}

The present invention relates to an active radio frequency identification tag and a location tracking method using the same. More specifically, by omitting the arrival time comparison procedure of the blink signal transmitted from the tag for location tracking, active radio frequency recognition is possible. Tag and its location tracking method.

The present invention is derived from research conducted as part of the IT growth engine technology development project of the Ministry of Knowledge Economy. [Task Management Number: 2008-S-040-01, Title: Real-time location tracking technology development]

FIG. 1 illustrates an air interface of a DSSS (Direct Sequence Spread Spectrum) signal transmitted from a Real Time Locating Systems (RTLS) tag proposed in ISO / IEC 24730-2.

As shown in FIG. 1, the RTLS tag transmits a blink signal modulated by a DSSS scheme at a blink interval of at least 5 seconds. Each blink is composed of N sublinks, and one of the four message formats proposed by ISO / IEC24730-2 can be selected and transmitted. The number of sublinks can be used from 1 to 8, and in order to obtain time diversity, the sublinks have a randomized subblink interval (subblink interval) of 125ms ± 16ms.

The position processor engine calculates the position by applying TDoA (Time Difference of Arrival) algorithm with the sub-blink arrival time information received from the RTLS reader. In order to calculate the location of the RTLS tag, subblink arrival time information received from at least three readers is required. The position processor engine needs to calculate the time difference of the sub-blink in order to apply the TDoA algorithm with the sub-blink arrival time information. In order to perform the accurate calculation, the sub-blink arrival time information obtained from the multiple readers is being transmitted during N sub-blink transmissions. It is necessary to group sub-blink arrival time information corresponding to the same number of transmission times. If grouping is wrong, time difference error of sub-blink interval (125ms ± 16ms) occurs and when calculating position of RTLS tag with this time information, position error much larger than 3m suggested by ISO / IEC24730-2 Cause.

FIG. 2 shows an example of calculating a location of each RTLS tag in a location processor engine when a blink is transmitted in several RTLS tags according to the ISO / IEC24730-2 standard. The location processor engine receives subblink arrival time information and tag ID values from multiple RTLS readers and groups them by the same tag ID. After grouping, subblink arrival time information is grouped for each RTLS tag position calculation. Find the fastest subblink arrival time information (t ₁ ) for each tag group, and find the arrival time information within 10ms based on the arrival time of the subblink transmitted at the same number of transmissions among the N subblinks transmitted from the RTLS tag. The subblink arrival time information is grouped. The search interval of 10ms is the subblink arrival time when the RTLS tag and the RTLS reader are separated by a maximum of 3km in consideration of the propagation speed, which is much larger than the 300m recognition distance of the RTLS tag and the RTLS reader defined in the ISO / IEC24730-2 standard. Because of the range, it can be regarded as a threshold sufficient for use in grouping sub-blink arrival time information.

After grouping the sub-blink arrival time information, if the number of sub-blink arrival time information of the group is three or more, the position calculation of the RTLS tag is applied by applying the TDoA algorithm, and after the position calculation, the arrival of the sub-blink corresponding to the next sub-blink. The process of finding and regrouping the time information is repeated. If the number of arrival time information is less than three, the process of searching for and regrouping the arrival time information of the sub-blink corresponding to the next sub-blink without repeating the position calculation is repeated. At this time, the boundary value used to find the arrival time information corresponding to the next sub-blink may be 100 ms in consideration of the sub-blink interval.

However, the previous method is inefficient because it needs to compare all the sub-blink arrival time information in order to group the sub-blink arrival time information required for the position calculation of the RTLS tag in the position processor engine.

Accordingly, an object of the present invention is to provide an active radio frequency identification tag and a location tracking method thereof, which can quickly track the location of a tag without comparing arrival time information of sublinks.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention, which are not mentioned above, can be understood by the following description, and more clearly by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

The present invention for achieving the object is an active tag, in the active tag to transmit a blink signal for position tracking, in each of the sub-blocks constituting the block signal, according to the time series generation order of each sub-blink It is characterized in that for transmitting the blink signal including the ID information.

The present invention also provides a method for tracking a location of an active tag by receiving a blink signal including subblink ID information according to a time series generation order of sublinks. A storage step of storing the ID information of the tag sending the signal, the sub-blink ID information and the arrival time information of each sub-blink in association with each other, the first grouping step of grouping the information stored in the storage step by the same tag ID, and the same tag ID. In the second grouping step and the second grouping step to group the information grouped by each sub-link ID, if there are three or more grouped sub-blink, the position calculation step of calculating the position of the active tag using the arrival time information of the sub-blink It is another feature to include.

According to the present invention as described above, when the active tag transmits a sub-blink in the RTLS system, by transmitting the sub-blink ID information corresponding to the order of the sub-blink, the location processor engine compares the sub-blink arrival time information Even if it is not, since the position can be easily calculated by arranging the sub-links sequentially using the sub-blink ID information, the position calculation is faster and more efficient than the conventional method.

The above objects, features, and advantages will be described in detail with reference to the accompanying drawings, whereby those skilled in the art to which the present invention pertains may easily implement the technical idea of the present invention. In describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

Hereinafter, first, an active RF tag according to an embodiment of the present invention will be described.

In the present invention, when the sub-blink signal arrives at the reader, the position processor engine (not shown) compares and groups the sub-blink signals by arrival time and tracks the position of the tag using the result. In order to omit the process of comparing the arrival times of the blink signals, sublink ID information according to a time series generation order is included in each sublink constituting the blink signal.

In more detail, the structure of the sub-blink signal transmitted from the tag according to the present invention is the same as that shown in FIG. 3. Sub-link is transmitted by storing the sub-blink ID information.

Here, the sub-blink ID information may be given according to the time-series order in which each sub-blink signal is generated. For example, referring to the blink signal illustrated in FIG. 1, one blink signal includes N sub-blink signals. In this case, subblock ID information of 1 to N is provided to each sublink signal.

Through this configuration, the present invention can omit the process in which the position processor engine compares the arrival time of the sub-blink signal one by one. More detailed description will be made below by explaining another position tracking method to the present invention.

4 illustrates a flow of a process of calculating a position of a tag by a location processor engine when receiving a sub-blink signal including sub-blink ID information according to an exemplary embodiment of the present invention.

According to FIG. 4, first, the location processor engine receives a blink signal from a tag through a reader (not shown) connected through a network or the like, and sends ID information of the tag that has sent the blink signal, subblink ID information, and each of the subblinks. The arrival time information is stored in association (S400).

Then, first, information stored in operation S400 (ID information of a tag that transmits a blink signal, subblink ID information, and arrival time information of each sublink) is grouped by tag ID (S402).

That is, by dividing the blink signal transmitted from a plurality of tags by tag, the information is classified by tag ID so as to know the movement path of each tag.

Then, in the present invention, in step S402, the information grouped by the tag ID is grouped again by the sublink ID (S404).

According to the present invention, since the sub-blink IDs are sequentially assigned according to the generated time series order, as described above, when grouping by the sub-blink IDs as described above, a plurality of readers receive one sub-blink signal. The arrival time of the blink is known accurately.

According to this configuration, the present invention may skip the process of comparing time information as in the prior art, and may be omitted due to an error that is unclearly grouped based on an experimentally set time (for example, 10 ms described in the background art). This can fundamentally solve the problem that the position of the tag could be incorrectly calculated.

On the other hand, in step S404 by determining the number of sub-links arranged in accordance with the order of the sub-blink ID (S406), if the number of the arranged sub-blink is less than three, the position tracking on the plane is impossible, so do not attempt to calculate the position of the tag It is preferable to discard the corresponding data without the first (S407).

On the contrary, when the arranged subblocks are three or more, the position of the active tag is calculated using the arrival time information of the sublinks (408).

Since the technique for calculating the position according to the arrival time of the signal is already known, a detailed description thereof will be omitted.

The calculated position of the tag may be transmitted to a separate server (not shown) for managing the tag position history together with the tag ID information.

5 illustrates a data processing procedure in an entire RTLS system according to a preferred embodiment of the present invention. As shown in FIG. 5, when receiving a blink signal through n readers, even if one of the sublinks is lost in a specific reader, three or more sublinks are input to the RTLS server grouped according to the sublink ID so that the tag is easily located. I can tell.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by.

1 is an exemplary diagram illustrating a structure of a blink signal.

2 is a flow chart of a position calculation method according to the prior art.

3 is a detailed structural diagram of a sublink signal transmitted according to an exemplary embodiment of the present invention.

4 is a flow chart of a position calculation method according to an embodiment of the present invention.

5 is an exemplary diagram illustrating a data processing procedure in an entire RTLS system according to a preferred embodiment of the present invention.

Claims (3)

In an active tag that sends a blink signal for location tracking, An active radio frequency identification tag, characterized in that for transmitting each of the sub-links constituting the block signal, the blink signal including the sub-link ID information according to the time series generation order of each sub-blink. The method of claim 1, The sublink ID information is And an active radio frequency identification tag included in the payload of the sublink. A method for tracking the position of an active tag by receiving a blink signal including sublink ID information according to a time series generation order of the sublink, A storing step of receiving a blink signal from the tag and storing ID information of the tag that has sent the blink signal, subblink ID information, and arrival time information of each subblink in association; A primary grouping step of grouping the information stored in the storing step by the same tag ID; A second grouping step of grouping information grouped by the same tag ID by sublink ID; And Calculating a position of an active tag by using arrival time information of the sublinks when there are three or more sublinks grouped in the secondary grouping step; Position tracking method of an active radio frequency identification tag comprising.

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