WO2017012409A1

WO2017012409A1 - Method and apparatus for locating rfid label

Info

Publication number: WO2017012409A1
Application number: PCT/CN2016/083178
Authority: WO
Inventors: 陈雷
Original assignee: 中兴通讯股份有限公司
Priority date: 2015-07-23
Filing date: 2016-05-24
Publication date: 2017-01-26
Also published as: CN106371059A

Abstract

A method and apparatus for locating an RFID label. The method comprises: collecting RSSI values of a to-be-located label and reference labels by using at least four read-write heads in a label region, to obtain at least four groups of RSSI values of the to-be-located label and the reference labels, wherein at least one to-be-located label and multiple reference labels are arranged in the label region (S101); and calculating to obtain location information of the to-be-located label by using a two-dimensional location algorithm and a triangle and centroid location algorithm according to the at least four groups of RSSI values of the to-be-located label and the reference labels (S102).

Description

RFID tag positioning method and device

Technical field

This document relates to, but is not limited to, the field of tag identification technology, and in particular, to an RFID tag positioning method and apparatus.

Background technique

Positioning systems are receiving more and more attention due to the requirements of positioning product targets in the fields of product manufacturing and sales, tracking and distribution of goods, and network wiring management. At present, common indoor positioning systems include cellular wireless positioning, wireless local area network positioning, infrared positioning, and ultrasonic positioning. With the increasing requirements for product positioning accuracy, the traditional positioning technology can no longer meet the requirements.

RFID (Radio Frequency Identification) technology is a non-contact automatic identification technology realized by radio frequency communication. Compared with other technologies, RFID technology has the advantages of non-contact, non-line-of-sight, high positioning accuracy, and no blind spots. RFID technology can also read a large amount of information from the target while positioning the object, realizing "one thing and one code", so RFID technology can quickly realize label positioning and data information exchange, which can reduce manpower and material resources and greatly improve recognition. And positioning efficiency. Positioning algorithm is the key to RFID positioning technology. Currently, RFID positioning technology is mainly divided into positioning algorithm of ranging technology and algorithm without ranging technology. Positioning algorithms based on ranging technology include TOA (time-of-arrival), TDOA (Time difference of Arrival) positioning, direction measurement positioning (AOA), and RSSI (Received Signal Strength Indication). Indicating) positioning; positioning algorithms based on no distance measurement technology include DV-HOP positioning algorithm, APIT positioning algorithm, and convex programming algorithm.

Passive RFID positioning in the related art employs a two-dimensional positioning method based on signal strength. Referring to Figure 1, the positioning technique is based on the theory of one-dimensional positioning, by placing four reference tags (r1/r2/r3/r4) and two remote read/write heads A and B indoors, through two sets of RSSI. The approximate polynomial of the value and the distance (r _X , r _{Y in} Fig. 1) can estimate the approximate position of the label P to be positioned, thereby realizing the two-dimensional positioning of the label. However, due to the multipath effect of the signal, there is an error in the received RSSI signal. In the absence of statistical error probability, the method achieves low positioning accuracy and large error, so the positioning method and device can only be applied to the positioning label distribution distance. Larger, less accurate positioning requirements, and under the condition of dense label distribution, the positioning accuracy of the positioning method can not distinguish the position of the label, and can not meet the application requirements.

Summary of the invention

The following is an overview of the topics detailed in this document. This Summary is not intended to limit the scope of the claims.

Embodiments of the present invention provide an RFID tag positioning method and apparatus, which can accurately locate and identify a tag under a label-intensive distribution condition.

The embodiments of the present invention adopt the following technical solutions.

A radio frequency identification RFID tag positioning method includes:

In the label area, the received signal strength indication RSSI value of the to-be-located tag and the reference tag is collected by four or more read/write heads, and four or more sets of the RSSI values of the to-be-positioned tag and the reference tag are obtained. The label area is arranged with one or more of the to-be-positioned labels, and a plurality of the reference labels;

The positioning information of the to-be-located tag is calculated according to the RSSI value of the four or more sets of the to-be-located tag and the reference tag, and combined with the two-dimensional positioning algorithm and the triangle centroid localization algorithm.

Optionally, in the label area, the RSSI values of the to-be-located tag and the reference tag are collected by four or more read/write heads, and the RSSI values of the four or more sets of the to-be-located tag and the reference tag are obtained. :

Collecting the ID information of each tag through the four or more read/write heads in a point-to-multipoint manner, and verifying the ID information collected by each of the read/write heads to determine each The ID information of each tag collected by the read/write head corresponds to the same; the label includes the to-be-positioned tag and the reference tag;

And each of the read/write heads interacts with each of the reference tags to obtain an RSSI value fed back by each of the reference tags according to the ID information of each tag collected, and each of the read/write heads and the The RSSI value of the tag to be located is obtained, and the RSSI value of the tag to be located and the reference tag of the four or more groups are obtained.

Optionally, in the label area, the label to be located is collected by four or more read/write heads and Refer to the RSSI value of the label to obtain four or more sets of the RSSI values of the to-be-positioned label and the reference label.

In the label area, the four or more read/write heads are evenly distributed to form a polygon, and each head corresponds to each vertex of the polygon;

Separating each of the reference labels on a polygonal frame formed by the read/write head;

The tag to be positioned is placed in an inner region of the polygon formed by the read/write head.

Optionally, the number of the to-be-positioned tags is multiple, and the plurality of to-be-positioned tags are randomly distributed inside the polygonal area formed by the read/write head.

Optionally, the determining, according to the RSSI value of the to-be-located tag and the reference tag, of the four or more groups, and the two-dimensional positioning algorithm and the triangle centroid positioning algorithm, calculating the positioning information of the to-be-located tag includes:

According to the two-dimensional positioning algorithm, the RSSI value of the four or more sets of the reference tags is brought into a preset approximate polynomial, and the function relationship polynomial is estimated, and the function relationship polynomial is the distance between the tag and the head. a polynomial of the correspondence between the AND and RSSI values;

And bringing the RSSI value of the tag to be located into the function relationship polynomial, and calculating preliminary positioning information of the four or more groups of the to-be-positioned tags;

The preliminary positioning information of the to-be-positioned tag is corrected according to a triangle centroid localization algorithm, and final positioning information of the to-be-located tag is obtained.

A radio frequency identification RFID tag positioning device comprises a head module, a monitoring management module and a plurality of reference labels, wherein:

The head module includes four or more read/write heads, and is disposed in the label area, and collects a received signal strength indication RSSI value of the to-be-positioned tag and the reference tag, and obtains four or more sets of the to-be-determined The RSSI value of the bit label and the reference label is fed back to the monitoring management module, and the label area is arranged with one or more of the to-be-positioned label and the plurality of reference labels;

The monitoring management module is configured to calculate the positioning information of the to-be-located tag according to the RSSI value of the to-be-located tag and the reference tag of the four or more groups, and the two-dimensional positioning algorithm and the triangle centroid positioning algorithm.

Optionally, the read/write head module collects the RSSI value of the to-be-located tag and the reference tag in the label area, and obtains four or more sets of the RSSI values of the to-be-located tag and the reference tag, including:

The head module adopts a point-to-multipoint manner, and collects ID ID information of each tag through the four or more read/write heads, and performs ID information collected by each of the read/write heads. To determine that the ID information of each tag collected by each of the read/write heads is the same; the tag includes the to-be-positioned tag and the reference tag; and according to the ID information of each tag collected, The read/write heads interact with each of the reference tags to obtain an RSSI value that is fed back by each of the reference tags, and each of the read/write heads interacts with the tag to be located to obtain the tag feedback of the to-be-positioned tag. The RSSI value of the four or more sets of RSSI values of the tag to be located and the reference tag are obtained.

Optionally, the device further includes: a configuration module, configured to evenly distribute the four or more read/write heads in the label area to form a polygon, and each of the read/write heads is corresponding to the Each vertex of the polygon; each of the reference labels is respectively disposed on a polygon frame formed by the head; and the label to be positioned is placed in an inner region of the polygon formed by the head.

Optionally, the to-be-positioned tag is a passive tag; the reference tag is evenly distributed on the polygon frame.

Optionally, the monitoring management module calculates the RSSI value of the to-be-located tag and the reference tag according to the four or more groups, and combines the two-dimensional positioning algorithm and the triangle centroid localization algorithm to calculate the to-be-located tag. Location information includes:

And the monitoring management module estimates, according to the two-dimensional positioning algorithm, the RSSI value of the four or more sets of the reference tags into a preset approximate polynomial, and estimates a function relationship polynomial, wherein the function relationship polynomial is a tag and a polynomial of the correspondence between the distance between the head and the RSSI value; bringing the RSSI value of the tag to be located into the function relationship polynomial, and calculating four or more groups of the to-be-positioned tags The preliminary positioning information is corrected according to the triangular centroid localization algorithm, and the final positioning information of the to-be-positioned label is obtained.

An RFID tag positioning method and device according to an embodiment of the present invention, in the tag area, collecting RSSI values of a tag to be located and a reference tag through at least four read/write heads, to obtain at least four groups to be located. The RSSI value of the label and the reference label is calculated according to the RSSI value of the at least four groups of the to-be-located label and the reference label, and combined with the two-dimensional positioning algorithm and the triangle centroid localization algorithm, the positioning information of the label to be located is calculated, The use of more than four heads combined with two-dimensional positioning algorithm and triangular centroid localization algorithm greatly reduces the positioning error of the label and improves the positioning accuracy of the label, which can be applied to the application scenario of dense label distribution.

Other aspects will be apparent upon reading and understanding the drawings and detailed description.

BRIEF abstract

1 is a schematic diagram of a two-dimensional positioning of a passive RFID tag in the related art;

2 is a basic structural diagram of approximate triangular centroid positioning in the related art;

3 is a schematic flow chart of a method for positioning an RFID tag according to a first embodiment of the present invention;

4 is a schematic diagram of a basic structure of an RFID tag positioning device according to a first embodiment of the present invention;

FIG. 5 is a schematic flowchart diagram of a method for positioning an RFID tag according to a second embodiment of the present invention; FIG.

6 is a schematic diagram of functional modules of an RFID tag positioning device according to a third embodiment of the present invention;

FIG. 7 is a schematic diagram of functional modules of an RFID tag positioning device according to a fourth embodiment of the present invention.

Embodiments of the invention

In the embodiment of the present invention, four or more read/write heads are used, and the distance between each adjacent two read/write heads and each reference label placed between the two read/write heads is known; Four or more sets of tag positioning information are estimated, and the final tag position is obtained by the triangle centroid positioning method, which can greatly improve the positioning accuracy of the tag, and can be applied to the application scenario of dense tag distribution.

Due to the multipath effect of the signal in the related art RFID tag positioning method, there is an error in the received RSSI signal. In the absence of a statistical error probability, the positioning accuracy achieved by the method is low and the error is large, so the positioning method and device are It can only be applied to scenes with large distribution distance and low precision positioning requirements. Under the condition of dense label distribution, the positioning accuracy of the positioning method can not distinguish the position of the label and can not meet the application requirements.

The embodiment of the invention provides a solution, which adopts more than four heads combined with a two-dimensional positioning algorithm and a triangle centroid localization algorithm, which can greatly improve the positioning accuracy of the label, and can be applied to an application scenario of dense label distribution. For example, but not limited to applications in logistics, smart identification cards, intelligent optical distribution networks, and the like.

First introduce the two-dimensional positioning algorithm and the triangle centroid localization algorithm.

For the two-dimensional positioning algorithm, referring to the two-dimensional positioning architecture diagram shown in FIG. 1, four electronic tags r1 to r4 are placed on the middle line of the head (or reader/writer) A and B. According to the empirical model and theoretical model of wireless signal propagation, the distance between the tag P to be read and written (A, B) (r _X , r _Y ), and the tag to be located detected by the head (A, B) The relationship of the RSSI values (S _X , S _Y ) can be expressed by the following polynomial:

r _X ≈a _X0 +a _X1 S ¹ _XN +a _X2 S ² _XN +a _X3 S ³ _XN +err

S _XN =S _X /S _max

r _Y ≈b _Y0 +b _Y1 S ¹ _YN +b _Y2 S ² _YN +b _Y3 S ³ _YN +err

S _YN =S _Y /S _max

The values of a _X0 , a _X1 , a _X2 , a _{X3 ,} and b _Y0 , b _Y1 , b _Y2 , and b _Y3 in the polynomial can be calculated by bringing the four sets of signal RSSI values fed back by the labels r1 to r4.

In addition, the optimum RSSI value read by the head is between 0 and 256. Substituting the read signal strength RSSI value Sp of the to-be-positioned tag P into the above polynomial, the position (r _X , r _Y ) of the tag can be obtained.

For the triangular centroid localization algorithm, see the approximate triangular centroid map shown in Figure 2.

After the reader/writer A/B/C receives the tag feedback signal RSSI, it records the three coordinate positions D1, D2, and D3 of the tag in the set location {(x1, y1), (x2, y2), (x3, y3). )}.

The centroid D of the triangle formed by D1, D2, and D3 is the final coordinate position of the label.

The positioning method can reduce the error of the position of the label position by the theory of statistical probability, and greatly improve the positioning accuracy.

Referring to FIG. 3, a first embodiment of the present invention provides an RFID tag positioning method, including the steps. S101～S102:

Step S101: Collect, in the label area, the RSSI value of the to-be-located tag and the reference tag by using at least four heads, and obtain RSSI values of at least four groups of the to-be-positioned tag and the reference tag, where the tag area is disposed with at least one Determining the positioning tag and the plurality of reference tags;

This embodiment is exemplified by four read/write heads. Through the two-dimensional positioning method, four sets of label distance information are estimated, and then the approximate triangular centroid positioning method is adopted to reduce the positioning error and obtain accurate label position. In this embodiment, the distance between any two adjacent read/write heads and each reference label placed between the two read/write heads is known.

Optionally, as shown in FIG. 4, the positioning apparatus involved in the positioning method includes: a read/write head module composed of four read/write heads, reference tags (R1 to R16), and a monitoring management module (or system). Position the label P to be treated.

The reference labels are respectively arranged on a rectangular frame formed by four read/write heads, and the four vertex positions of the rectangle are respectively placed on the read/write heads A, B, C, and D, and the to-be-positioned label P is placed at any position inside the rectangle. If there are more than four heads, each head is evenly distributed to form a polygon, and each head corresponds to each vertex of the polygon; each reference label is separately placed by reading and writing. The polygon frame formed by the head; the label to be positioned is placed in an inner region of the polygon formed by the head.

The tags to be located may be a single tag or multiple, and are randomly distributed inside the polygonal area formed by the read/write head; but may be, but not limited to, uniformly distributed into an N×M type tag array; N and M are positive integers.

Each of the read/write heads is configured to identify the identity (ID) information of the tag, and in addition, the read/write head is further configured to measure the distance between the tag and each of the read/write heads.

The tag to be located is set to identify the target to be located.

Optionally, the to-be-positioned label may be a passive label; the to-be-positioned label may be uniformly and randomly distributed inside the rectangle, and the reference label is evenly placed on the rectangular side line. Of course, in other alternatives, the to-be-positioned label and the reference label may be placed in other manners, which are not limited herein.

The label area of this embodiment is formed by the above architecture.

In the tag area, the RSSI values of the tag to be located and the reference tag are collected through four read/write heads to obtain The RSSI values of the four sets of tags to be located and the reference tags.

Optionally, as an implementation manner, the step S101 includes:

In a point-to-multipoint manner, the ID information of each tag is collected by the at least four read/write heads, and the ID information collected by each read/write head is verified to determine each of the read/write heads collected. The ID information of the labels is the same; the label includes the to-be-located label and the reference label; and each of the read/write heads interacts with each reference label according to the collected ID information of each label to obtain each Referring to the RSSI value of the tag feedback, the RSSI value of the tag to be located is obtained by interacting with the tag to be located, and the RSSI value of at least four groups of the tag to be located and the reference tag is obtained.

Wherein, when one of the read/write heads interacts with the reference tag, it can only interact with each reference tag in the communication range of the read/write head.

Optionally, the collecting process of the positioning device shown in FIG. 4 includes the following steps 401-406:

401. Start P2MP, (point to multiple point, ID reading process).

First, the head A is opened, and the ID information of all the labels (including the label to be positioned and the reference label) is read into the head A. Read and close head A after reading. Then, the heads B, C, and D are sequentially turned on to execute the same process as described above.

402. Compare the ID information of all the tags read by the heads A, B, C, and D. If the ID information read by all the heads is completely consistent, skip to the process of step 403; if the ID information is inconsistent, Skip to the flow of step 401, that is, re-read.

403. Start a reference label positioning process.

First, the ID of the reference tag R1 is selected, and the ID query command is issued by the read/write head A. After receiving the command, the reference tag R1 matches the self ID, and if the IDs match, the feedback information is transmitted to the read/write head A. If they are inconsistent, they will be ignored. The head A acquires the RSSI value of the reference tag R1 according to the signal fed back by the tag, and uploads the result to the monitoring management module.

According to the above process, the head A obtains the feedback signals of the labels R1 to R4 and R13 to R16, respectively, thereby obtaining the RSSI values of the labels, and uploading all the measurement results to the monitoring management module.

404. According to the process of step 403, start the positioning process of the head B, and the head B respectively The feedback signals of the labels R1 to R4 and R5 to R8 are obtained, thereby obtaining the RSSI values of the labels. The positioning process of the head C is started, and the head C obtains the feedback signals of the labels R5 to R8 and R9 to R12, respectively, thereby obtaining the RSSI values of the labels. The positioning process of the head D is started, and the head D obtains the feedback signals of the labels R9 to R12 and R13 to R16, respectively, thereby obtaining the RSSI values of the labels. All measurement results are uploaded to the monitoring management module.

405. Start a label positioning process to be located.

First, the ID of the tag P to be located is selected, and the ID query command is sent by the head A. After the tag is received, the tag is compared with the self ID. If the IDs are consistent, the feedback information is transmitted. If they are inconsistent, they will be ignored. The head A acquires the RSSI value of the tag P to be located according to the signal fed back by the tag, and uploads the result to the monitoring management module.

406. According to the process of 405, the read/write heads B, C, and D respectively obtain the RSSI values fed back by the tag P to be located, and upload the result to the monitoring management module.

Through the above process, the RSSI values of the four sets of tags to be located and the reference tags are obtained.

Step S102: Calculate positioning information of the to-be-located tag according to the RSSI value of the at least four groups of the to-be-located tag and the reference tag, and the two-dimensional positioning algorithm and the triangle centroid positioning algorithm.

Optionally, the step S102 includes:

And according to the two-dimensional positioning algorithm, the RSSI value of the at least four sets of reference tags is brought into a preset approximate polynomial, and the function relationship polynomial is estimated, the function relationship polynomial is the distance between the tag and the read/write head, and the RSSI value is a polynomial of correspondence between;

And bringing the RSSI value of the tag to be located into the function relationship polynomial, and calculating preliminary positioning information of at least four groups of tags to be located;

And correcting the preliminary positioning information of the to-be-located tag according to the triangle centroid positioning algorithm, to obtain final positioning information of the tag to be located.

Optionally, the processing procedure of the monitoring management module in the apparatus shown in FIG. 4 is as follows:

According to the uploaded result, the monitoring management module can estimate the four approximate coordinate positions D1 (dx1, dy1), D2 (dx2, dy2), D3 (dx3, dy3) of the tag to be located according to the two-dimensional positioning method shown in FIG. ), D4 (dx4, dy4).

The monitoring management module can form four triangles according to the triangle centroid positioning method, coordinate positions (D1, D2, D3), (D1, D2, D4), (D2, D3, D4), (D1, D3, D4). The center of the four triangles positions the four label positions. Then, according to the magnitude of the error value, the one with the largest position error of the centroid is excluded, and the remaining three centroid positions can form a triangle, and the centroid of the triangle is the precise label position of the label to be positioned.

Performing the above steps for different tags to be located can complete the positioning and identification of all tags to be located.

Based on the two-dimensional positioning method, the solution of the embodiment increases the number of reading and writing heads, estimates two at least four sets of label distance information through the two-dimensional positioning method, and reduces the positioning error by approximating the triangular centroid positioning method. Accurate label position greatly improves the positioning accuracy of the label and can be applied to dense label distribution scenes.

Referring to FIG. 5, a second embodiment of the present invention provides an RFID tag positioning method, which is based on the first embodiment shown in FIG. 3, except that in the above step S101: collecting at least four read/write heads in the tag area. The RSSI value of the to-be-located tag and the reference tag further includes: at least four sets of the RSSI values of the to-be-located tag and the reference tag:

Step S100, in the label area,

And uniformly arranging the at least four heads to form a polygon, each head corresponding to each vertex of the polygon; each reference label is respectively disposed on a polygon frame formed by the head; The tag to be positioned is placed in an inner region of the polygon formed by the head.

Taking the four read/write heads shown in FIG. 4 as an example, the reference labels are respectively arranged on a rectangular frame composed of four read/write heads, and the four vertex positions of the rectangle are respectively placed on the readers A, B, C, and D. The tag P to be positioned can be placed anywhere inside the rectangle.

In this embodiment, the RSSI value of the to-be-located tag and the reference tag is collected by the at least four read/write heads in the label area, and the RSSI values of the at least four sets of the to-be-located tag and the reference tag are obtained, according to the at least four groups. Determining the RSSI value of the positioning tag and the reference tag, and combining the two-dimensional positioning algorithm and the triangle centroid localization algorithm to calculate the positioning information of the tag to be located, by using four or more read/write heads combined with a two-dimensional positioning algorithm and Triangle centroid localization algorithm, greatly reducing the standard The positioning error of the sign improves the positioning accuracy of the tag, and can be applied to an application scenario of dense tag distribution.

As shown in FIG. 6, the third embodiment of the present invention provides an RFID tag positioning apparatus, including a head module 201, a monitoring management module 202, and a plurality of reference tags 203, wherein:

The read/write head module 201 includes at least four read/write heads, and is configured to collect RSSI values of the to-be-located tags and the reference tags in the tag area, to obtain RSSI values of at least four groups of the to-be-positioned tags and reference tags. Feedback to the monitoring management module 202, the label area is arranged with at least one of the to-be-positioned label and the plurality of reference labels;

The monitoring management module 202 is configured to calculate the positioning information of the to-be-located tag according to the RSSI value of the at least four groups of the to-be-located tag and the reference tag, and the two-dimensional positioning algorithm and the triangle centroid positioning algorithm.

In this embodiment, the distance between any two adjacent read/write heads and each reference label placed between the two read/write heads is known.

Optionally, the read/write head module 201 collects the RSSI value of the to-be-located label and the reference label in the label area, and obtains RSSI values of the at least four groups of the to-be-located label and the reference label, including:

The head module 201 adopts a point-to-multipoint method, collects ID information of each tag through at least four heads, and checks ID information collected by each head to determine each read. The ID information of each label collected by the write header corresponds to the same; the label includes the to-be-positioned label and the reference label; and each read/write head and each reference label are used according to the ID information of each collected label. Interacting, obtaining an RSSI value that is fed back by each reference tag, and interacting with the tag to be located by each read/write head to obtain an RSSI value fed back by the tag to be located, and obtaining at least four sets of the to-be-positioned tag and the reference tag. RSSI value.

The monitoring management module 202 calculates the positioning information of the to-be-located tag according to the RSSI value of the at least four groups of the to-be-located tag and the reference tag, and the two-dimensional positioning algorithm and the triangle centroid positioning algorithm.

The monitoring management module 202 brings the RSSI value of the at least four sets of reference tags into a preset approximate polynomial according to a two-dimensional positioning algorithm, and estimates a function relationship polynomial, and the function relationship is multi-function a polynomial of the correspondence between the tag and the head and the RSSI value; the RSSI value of the tag to be located is brought into the function relationship polynomial, and at least four groups of the tag to be located are calculated. The preliminary positioning information is corrected according to the triangular centroid localization algorithm, and the final positioning information of the to-be-located label is obtained.

This embodiment is exemplified by four read/write heads. Through the two-dimensional positioning algorithm, four sets of tag distance information are estimated, and then the approximate triangle centroid localization algorithm is used to reduce the positioning error and obtain accurate label position.

As shown in FIG. 4, the positioning device involved in the example includes: a head module composed of four read/write heads, reference tags (R1 to R16), and a monitoring management module (or system) for positioning the tag P. Positioning.

The tag to be located is set to identify the target to be located.

The label area of this embodiment is formed by the above architecture.

In the label area, the RSSI values of the to-be-located tag and the reference tag are collected by four read/write heads, and the RSSI values of the four sets of the tag to be located and the reference tag are obtained.

Optionally, as an implementation manner, the read/write head module adopts a point-to-multipoint manner, and collects ID information of each tag through each read/write head, and collects ID information of each read/write head. Performing a check to determine that the ID information of each tag collected by each read/write head corresponds to the same; according to the ID information of each tag collected, each read/write head interacts with each reference tag to obtain each reference. The RSSI value of the tag feedback is obtained by interacting with the tag to be located by each of the read/write heads, and the RSSI value of the tag to be located is obtained, and the RSSI values of the four sets of the tag to be located and the reference tag are obtained.

The acquisition process of the apparatus shown in FIG. 4 includes the following steps 401-406:

401. Start the point-to-multipoint ID reading process.

403. Start a reference label positioning process.

404. According to the process of step 403, the positioning process of the read/write head B is started, and the read/write head B obtains the feedback signals of the labels R1 R4 and R5 to R8 respectively, thereby obtaining the RSSI values of the labels. The positioning process of the head C is started, and the head C obtains the feedback signals of the labels R5 to R8 and R9 to R12, respectively, thereby obtaining the RSSI values of the labels. The positioning process of the head D is started, and the head D obtains the feedback signals of the labels R9 to R12 and R13 to R16, respectively, thereby obtaining the RSSI values of the labels. All measurement results are uploaded to the monitoring management module.

405. Start a label positioning process to be located.

Then, the monitoring management module in the device shown in FIG. 4 calculates the to-be-located tag P according to the RSSI value of the four groups of the to-be-located tag and the reference tag, and the two-dimensional positioning algorithm and the triangle centroid positioning algorithm. Location information.

The process is as follows: according to the two-dimensional positioning algorithm, the RSSI values of the four sets of reference tags are brought into a preset approximate polynomial, and the function relationship polynomial is estimated, the function relationship polynomial is the distance between the tag and the head, and the RSSI value. a polynomial of correspondence between;

And bringing the RSSI value of the tag to be located into the function relationship polynomial, and calculating preliminary positioning information of four groups of tags to be located;

Optionally, in the apparatus shown in FIG. 4, the processing process of the monitoring management module is as follows:

Performing the above steps for different tags to be located, you can complete all the targets to be located. Signing and identification.

As shown in FIG. 7, a fourth embodiment of the present invention provides an RFID tag positioning apparatus, which is based on the third embodiment shown in FIG.

The configuration module 200 is configured to uniformly distribute the at least four heads in the label area to form a polygon, each head corresponding to each vertex of the polygon; and each reference label is respectively placed by the reading The polygon frame formed by the write head; the label to be positioned is placed in an inner region of the polygon formed by the head.

In this embodiment, the RSSI value of the to-be-located tag and the reference tag is collected by the at least four read/write heads in the label area, and the RSSI values of the at least four sets of the to-be-located tag and the reference tag are obtained, according to the at least four groups. Determining the RSSI value of the positioning tag and the reference tag, and combining the two-dimensional positioning algorithm and the triangle centroid localization algorithm to calculate the positioning information of the tag to be located, by using four or more read/write heads combined with a two-dimensional positioning algorithm and The triangle centroid localization algorithm greatly reduces the positioning error of the tag and improves the positioning accuracy of the tag, and can be applied to the application scenario of dense tag distribution.

Industrial applicability

An RFID tag positioning method and apparatus according to an embodiment of the present invention, in the tag area, collecting RSSI values of a tag to be located and a reference tag by using at least four heads, and obtaining RSSI values of at least four groups of tags to be located and reference tags Calculating the to-be-positioned flag according to the RSSI value of the at least four groups of the to-be-positioned tag and the reference tag, and combining the two-dimensional positioning algorithm and the triangle centroid localization algorithm The positioning information of the sign, because of the use of more than four heads combined with the two-dimensional positioning algorithm and the triangle centroid positioning algorithm, greatly reduces the positioning error of the tag, improves the positioning accuracy of the tag, and can be applied to dense tag distribution. Application scenario.

Claims

A radio frequency identification RFID tag positioning method includes:

In the label area, the received signal strength indication RSSI value of the to-be-located tag and the reference tag is collected by four or more read/write heads, and four or more sets of the RSSI values of the to-be-positioned tag and the reference tag are obtained. The label area is arranged with one or more of the to-be-positioned labels, and a plurality of the reference labels;

The positioning information of the to-be-located tag is calculated according to the RSSI value of the four or more sets of the to-be-located tag and the reference tag, and combined with the two-dimensional positioning algorithm and the triangle centroid localization algorithm.
The method according to claim 1, wherein in the tag area, the RSSI values of the tag to be located and the reference tag are collected by four or more read/write heads to obtain four or more sets of the tags to be located. And the RSSI values of the reference tags include:

Collecting the ID information of each tag through the four or more read/write heads in a point-to-multipoint manner, and verifying the ID information collected by each of the read/write heads to determine each The ID information of each tag collected by the read/write head corresponds to the same; the label includes the to-be-positioned tag and the reference tag;

And each of the read/write heads interacts with each of the reference tags to obtain an RSSI value fed back by each of the reference tags according to the ID information of each tag collected, and each of the read/write heads and the The RSSI value of the tag to be located is obtained, and the RSSI value of the tag to be located and the reference tag of the four or more groups are obtained.
The method according to claim 1, wherein in the tag area, the RSSI values of the tag to be located and the reference tag are collected by four or more read/write heads to obtain four or more sets of the tags to be located. And the RSSI value of the reference label also includes:

In the label area, the four or more read/write heads are evenly distributed to form a polygon, and each head corresponds to each vertex of the polygon;

Separating each of the reference labels on a polygonal frame formed by the read/write head;

The tag to be positioned is placed in an inner region of the polygon formed by the read/write head.
The method according to claim 3, wherein the plurality of tags to be located are multiple The positioning tag is randomly distributed inside the polygon area formed by the head.
The method according to any one of claims 1 to 4, wherein the RSSI value according to the four or more sets of the to-be-positioned tag and the reference tag is combined with a two-dimensional positioning algorithm and a triangular centroid localization algorithm, Calculating the positioning information of the to-be-located tag includes:

According to the two-dimensional positioning algorithm, the RSSI value of the four or more sets of the reference tags is brought into a preset approximate polynomial, and the function relationship polynomial is estimated, and the function relationship polynomial is the distance between the tag and the head. a polynomial of the correspondence between the AND and RSSI values;

And bringing the RSSI value of the tag to be located into the function relationship polynomial, and calculating preliminary positioning information of the four or more groups of the to-be-positioned tags;

The preliminary positioning information of the to-be-positioned tag is corrected according to a triangle centroid localization algorithm, and final positioning information of the to-be-located tag is obtained.
A radio frequency identification RFID tag positioning device comprises a head module, a monitoring management module and a plurality of reference labels, wherein:

The head module includes four or more read/write heads, and is disposed in the label area, and collects a received signal strength indication RSSI value of the to-be-positioned tag and the reference tag, and obtains four or more sets of the to-be-determined The RSSI value of the bit label and the reference label is fed back to the monitoring management module, and the label area is arranged with one or more of the to-be-positioned label and the plurality of reference labels;

The monitoring management module is configured to calculate the positioning information of the to-be-located tag according to the RSSI value of the to-be-located tag and the reference tag of the four or more groups, and the two-dimensional positioning algorithm and the triangle centroid positioning algorithm.
The apparatus according to claim 6, wherein

The read/write head module collects the RSSI value of the to-be-located tag and the reference tag in the label area, and obtains four or more sets of the RSSI values of the to-be-located tag and the reference tag, including:

The head module adopts a point-to-multipoint manner, and collects ID ID information of each tag through the four or more read/write heads, and performs ID information collected by each of the read/write heads. To determine that the ID information of each tag collected by each of the read/write heads is the same; the tag includes the to-be-positioned tag and the reference tag; and according to the ID information of each tag collected, The read/write head interacts with each of the reference tags to obtain an RSSI fed back by each of the reference tags And the RSSI value of the to-be-positioned tag is obtained by the interaction between the read/write head and the to-be-located tag, and the RSSI value of the four or more sets of the to-be-located tag and the reference tag is obtained.
The apparatus of claim 6 further comprising:

a configuration module, configured to evenly distribute the four or more read/write heads in the label area to form a polygon, each of the read/write heads corresponding to each vertex of the polygon; The reference labels are respectively disposed on the polygonal frame formed by the read/write head; and the label to be positioned is placed in the inner region of the polygon formed by the read/write head.
The apparatus according to claim 8, wherein the plurality of tags to be located are plural, and the plurality of tags to be located are randomly distributed inside a polygonal area formed by the head.
The apparatus according to claim 9, wherein

The tag to be located is a passive tag; the reference tag is evenly distributed on the polygonal frame.
The apparatus according to any one of claims 6 to 10, wherein

The monitoring management module calculates the positioning information of the to-be-located tag according to the RSSI value of the four or more groups of the to-be-located tag and the reference tag, and the two-dimensional positioning algorithm and the triangle centroid positioning algorithm.

And the monitoring management module estimates, according to the two-dimensional positioning algorithm, the RSSI value of the four or more sets of the reference tags into a preset approximate polynomial, and estimates a function relationship polynomial, wherein the function relationship polynomial is a tag and a polynomial of the correspondence between the distance between the head and the RSSI value; bringing the RSSI value of the tag to be located into the function relationship polynomial, and calculating four or more groups of the to-be-positioned tags The preliminary positioning information is corrected according to the triangular centroid localization algorithm, and the final positioning information of the to-be-positioned label is obtained.