A tag positioning method based on RFID technology

Abstract

The present invention discloses a tag positioning method based on RFID technology, which mainly eliminates the positioning position interference problem caused by a single tag being read by multiple antennas. The method adopts the steps of designing a three-dimensional spatial model of the positioning area and combining it with a positioning algorithm for judgment. The interference values ​​are eliminated in sequence by using the advantages and disadvantages of the antenna spatial points, an RSSI ranking table combined with a tag data information table, and the weighted total score of the three major influencing factors of the tag data information. The method realizes the precise positioning of multiple tags in the application scenario, further reduces the misjudgment results, and improves the positioning accuracy of the tags.

Description

Technical Field

[0001] The present invention belongs to the field of RFID technology, and in particular to a tag positioning method based on RFID technology. Background Art

[0002] With the widespread adoption of RFID tags, RFID technology is being used in an increasing number of scenarios, such as dynamic warehouse material inflow and outflow management and static document storage management. During use, an RFID tag is typically affixed to the object being managed. An RFID reader and antenna emit electromagnetic waves that cover the area where the RFID-tagged object is located, enabling communication between the reader and the tag and completing the tag reading. However, in actual use, the electromagnetic waves emitted by the RFID reader and antenna may reach locations other than the tag being read, making cross-reading and missed readings a common problem.

[0003] Specifically, (1) cross-reading refers to the area covered by the electromagnetic waves emitted by the antenna, which enables the RFID reader to read not only the tag of the object to be read, but also the tags at other locations around it. The reason for cross-reading is: the field strength distribution characteristics of the antenna. Different antennas have different field strength distribution ranges and strengths. As a result, the boundaries of the field strength area cannot be completely fixed. Therefore, when used in actual environments, it is inevitable that the reader will read surrounding tags, causing cross-reading. When other factors remain unchanged, when the antenna power is higher, the possibility of cross-reading is greater, and when the antenna power is lower, the possibility of cross-reading is lower.

[0004] (2) Missed reads: Due to the physical characteristics of RFID technology, when multiple tags completely overlap or the overlap rate is very high, the reader cannot read / count all target object tags. The higher the antenna power, the lower the missed read rate, and vice versa.

[0005] Therefore, cross-reading and missed reads are inherently conflicting factors. Increasing antenna power reduces missed reads, but cross-reading becomes more pronounced. Reducing antenna power improves cross-reading, but miss reads increase. Therefore, it's necessary to fundamentally improve the antenna's field strength distribution, avoiding weak and blind spots, ensuring a uniform field strength distribution and a controllable range.

[0006] Especially in the storage and positioning management of items, if the label of each item can be accurately read and the location of each item can be accurately located, the management efficiency of these items can be greatly improved.

[0007] In the prior art, such as the Chinese patent publication number CN111079874A, "A Modular Tag Positioning System and Method Based on RFID Technology," the disclosed modular tag positioning method discloses that, during the process of tag inventorying by the RFID reader / writer using the antenna array module, a tag is often read by multiple antennas, resulting in interference values. When calculating the tag position, it is necessary to combine the number of times the tag is counted with the antenna inventory result data to filter and determine the tag's location. However, during this screening process, the only way to filter out the interference value is through the threshold setting operation. That is, if the number of times a certain antenna has counted the tag is less than the set threshold, the inventory result of the antenna is discarded. Setting the threshold in this operation is a very critical operation. If the threshold setting is unreasonable, data that should not be discarded will be discarded, or data that should be discarded will be included in the data table, resulting in excessive inaccurate data being mixed in the subsequent parabola generation process, thereby resulting in inaccurate final tag positioning. In short, the practice of excluding data by simply relying on threshold settings may have a greater risk of missing correct data, which in turn affects the final label positioning accuracy and produces more misjudgment results. Summary of the Invention

[0008] In order to overcome the shortcomings of the existing technology, the present invention provides a tag positioning method based on RFID technology. The RFID tag positioning method performs multi-step investigation and positioning on the interference values ​​that appear when a single tag is read by multiple antennas, further reducing misjudgment results and improving the positioning accuracy of the tagged items.

[0009] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a tag positioning method based on RFID technology, comprising the following steps: ① arranging antenna array modules in a designated positioning area, partitioning the designated positioning area into multiple spatial positions, and numbering these spatial positions in sequence, which are called spatial points. Each antenna corresponds to a spatial point, and each antenna array is connected to the antenna splitter of the RFID reader; ② after the RFID reader receives the command from the host computer to locate and inventory the items with RFID tags in the positioning area, it completes the data inventory of the tags in the positioning area, obtains the RSSI signal value of the tag in the positioning area each time it is inventoried, the number of times the tag is inventoried by each antenna per unit time, and the antenna number of each tag inventoried, and inputs them into the data processing module running on the host computer; it is characterized in that ③ the spatial point position of each antenna in the antenna array is input into the antenna splitter of the data processing module A three-dimensional spatial model of the antenna array is formed in the linear array three-dimensional space generation module, in which the antennas are distributed in spatial points based on the antenna feed point, and the closer the spatial point of the antenna is to the center of the three-dimensional spatial model, the better its position; ④ The RSSI signal value of each tag each time it is counted, the number of times each tag is counted by each antenna per unit time, and the antenna number of the tag counted are input into the tag data information table generation module in the data processing module to generate a tag data information table for each tag, and after sorting and calculating according to the strength of the RSSI signal value in the tag data information table, an RSSI sorting table of the tag data information table is obtained; ⑤ The tag positioning algorithm module in the data processing module performs tag positioning processing based on the advantages and disadvantages of the spatial point of the antenna in the three-dimensional spatial model of the antenna array and the RSSI sorting table of the tag data information table, and then outputs the optimal antenna spatial point as the positioning position of the tag and transmits it to the host computer.

[0010] Furthermore, in step ⑤, the tag positioning algorithm processing includes the following processes: (1) If the RSSI signal value of the tag read by a certain antenna number and the ranking of the number of times the tag is read are both optimal in the RSSI sorting table of the tag data information table, then the spatial point where the antenna number in the tag data information table is located is output as the positioning position of the tag; (2) If the RSSI signal value of the tag read by a certain antenna number and the ranking of the number of times the tag is read are not both optimal in the RSSI sorting table of the tag data information table, then the spatial point where the antenna number in the optimal tag data information table is located is output as the positioning position of the tag according to the weighted total score ranking of the RSSI signal value, the number of times the tag is read and the spatial point of the antenna number in the tag data information table.

[0011] Furthermore, when the situation (2) occurs in step ⑤, the two antenna numbers corresponding to the first two RSSI signal values ​​are selected from the RSSI sorting table of the tag data information table, and if the spatial point positions of the two antenna numbers are consistent, the spatial point position of the antenna is output as the positioning position of the tag; if the spatial point positions of the two antenna numbers corresponding to the first two RSSI signal values ​​in the RSSI sorting table of the tag data information table are inconsistent, when one of the RSSI signal values ​​is greater than the other RSSI signal value by a set threshold value ω, the spatial point position of the antenna number corresponding to the RSSI signal value with a larger value is selected as the positioning position of the tag; If the difference between the first two RSSI signal values ​​in the RSSI sorting table of the tag data information table is less than the set threshold ω, the two read times corresponding to the two RSSI signal values ​​are selected for comparison. When the read times of one of them is higher than the other by a set threshold σ, the spatial point position of the antenna number corresponding to the larger read times is selected as the positioning position of the tag; if the difference between the two read times is less than the set threshold σ, the spatial point position of the optimal antenna number is output as the positioning position of the tag according to the total weight score of the RSSI signal values, read times and spatial points of the antenna numbers in the two tag data information tables.

[0012] Furthermore, the weighted total score in step ⑤ is calculated according to the weight formula: weight (antenna number spatial point) × coefficient (antenna number spatial point) + weight (RSSI) × coefficient (RSSI) + weight (number of times read) × coefficient (number of times read) = total score, wherein weight (antenna number spatial point) > weight (RSSI) > weight (number of times read), and the two tag data information tables are sorted by the total scores calculated according to the weight formula, and the spatial point where the antenna number in the tag data information table with the highest total score is located is selected as the tag positioning position.

[0013] By adopting the above scheme, the present invention uses a three-dimensional spatial model combined with a positioning algorithm to judge the interference value caused by a single tag being read by multiple antennas, and uses the advantages and disadvantages of the antenna spatial points, the RSSI ranking table combined with the tag data information table, and the weighted total score of the three major influencing factors of the tag data information to eliminate the interference value, thereby achieving precise positioning of multiple tags in the application scenario and further improving the positioning accuracy of the tags.

[0014] The present invention will be further described below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Attachment Figure 1 A flowchart of the present invention for establishing a three-dimensional spatial model of an antenna array and outputting the positioning results of the tag in combination with a tag positioning algorithm;

[0016] Attachment Figure 2This is a flowchart of the positioning result of a single antenna after the antenna array algorithm has obtained the precise location of the existing tag.

[0017] Attachment Figure 3 A three-dimensional spatial model diagram of an antenna array according to a specific embodiment of the present invention;

[0018] Attachment Figure 4 The tag data information table of a specific embodiment of the present invention is ranked by RSSI value to form an RSSI ranking table;

[0019] Attachment Figure 5 This is a flowchart of the positioning algorithm process of a specific embodiment of the present invention. DETAILED DESCRIPTION

[0020] Specific embodiments of the present invention are Figure 1-5 The figure shows a tag positioning method based on RFID technology, which includes the following steps: first, an antenna array module is arranged in a designated positioning area, and the designated positioning area is partitioned into multiple spatial positions. Each antenna in the antenna array corresponds to a spatial position in the positioning area, and these spatial positions are numbered in sequence and are called spatial points. x , so each antenna corresponds to a spatial point O x The antenna array module is connected to the antenna splitter of the RFID reader, and the RFID reader is connected to the host computer running the human-computer interaction module and the data processing module. The user operates the system through the human-computer interaction module to locate the items with RFID tags placed in the positioning area. After the RFID reader receives the command to locate the items from the host computer, the antenna splitter on the RFID reader traverses each antenna inventory tag on each antenna array, obtains the RSSI signal value of each tag in the positioning area each time it is inventoried, the number of times each tag is inventoried by each antenna per unit time (such as a patrol cycle), and the antenna number of the inventory tag, and inputs them into the data processing module running on the host computer.

[0021] Secondly, the antenna array three-dimensional space generation module in the data processing module forms a three-dimensional space model of the antenna array according to the spatial point position of each antenna in the antenna array, wherein the antennas are distributed in the spatial point position with their respective feed points as point units. Therefore, in this embodiment, Figure 3As shown, one spatial point has two antenna numbers, that is, there are 12 spatial points and 24 antenna numbers. When designing a specific model, the three-dimensional structure can be designed 1:1 through three-dimensional software according to the specific structure of the positioning area. At the same time, the antenna feed point can be positioned in the specific position of the positioning area based on the three-dimensional coordinate system. Or it can be based on the specific form of the three-dimensional structure. For example, the file cabinet in this embodiment has been partitioned to form 12 spatial positions. Then, these 12 spatial positions can be numbered and the two antenna numbers distributed therein can be matched, as shown in FIG. Figure 3 In the figure, the spatial point where antenna numbers 1 and 2 (Ant, 1Ant2) are located is O1, and they are distributed in the corresponding order.

[0022] Among them, when the RFID reader receives the command from the host computer to inventory the tags, the RFID reader traverses all the tag information read by each antenna in the antenna array. The tag information includes the RSSI signal value of each tag read by the antenna array, the number of times the tag is read, which antennas read the tag, etc. After the above tag information is input into the tag data information table generation module in the data processing module, a tag data information table is formed. The tag data information table contains the reflected signal value RSSI of each tag each time it is inventoryed. x , the number of times each tag is counted by each antenna per unit time Cnt x And the antenna number Ant that is counted to the label x (That is, the tag data information table contains RSSI x 、Cnt x 、Ant x ). In addition, according to the antenna number Ant x Corresponding to its spatial point (spatial position) in the three-dimensional space model (three-dimensional file cabinet) O X Preferably, adding the spatial point corresponding to the antenna number to the tag data information table is more helpful for the subsequent positioning result calculation; then, the tag data information table is ranked according to the RSSI value to form an RSSI ranking table such as Figure 4 shown.

[0023] Next, the positioning algorithm is combined with the RSSI sorting table of the tag data information table and the advantages and disadvantages of the spatial point position of the tag's antenna number in the three-dimensional spatial model of the antenna array. After integration processing, the optimal antenna spatial point position is output as the positioning position of the tag and transmitted to the host computer.

[0024] Of course, if a tag is only read by one antenna, the spatial point where that antenna number is located can be directly output as the tag location. However, the same tag can often be read by multiple antennas within a certain range, so interference information needs to be eliminated.

[0025] The specific positioning algorithm process is as follows: Under normal circumstances, according to the antenna array design, the distribution pattern of RSSI value and number is: the closer the tag is to the antenna array, the better the RSSI value, and the more times it is read in the same inventory cycle, and vice versa. Therefore, if (1) the RSSI signal value of the tag read by a certain antenna number and the ranking of the number of times the tag is read are both the best in the RSSI sorting table of the tag data information table, it means that the antenna number is closest to the tag, that is, the spatial point where the antenna number in the tag data information table is located is output as the positioning position of the tag; (2) if the RSSI signal value of the tag read by a certain antenna number and the ranking of the number of times the tag is read are not both the best in the RSSI sorting table of the tag data information table, then the two antenna numbers corresponding to the top two RSSI signal values ​​are selected from the RSSI sorting table of the tag data information table, and if the spatial point positions of the two antenna numbers are consistent, then the spatial point positions of the antennas are output as the positioning position of the tag; (3) if the spatial point positions of the two antenna numbers corresponding to the top two RSSI signal values ​​in the RSSI sorting table of the tag data information table are inconsistent, then when one of the RSSI signal values ​​is greater than the other RSSI signal value by a set threshold value ω (the set threshold value ω is initialized to 5dB, and can be subsequently According to the debugging and testing process, and then adjust the initialization assignment based on experience), the spatial point of the antenna number corresponding to the larger RSSI signal value is selected as the positioning position of the tag; (4) If the difference between the first two RSSI signal values ​​in the RSSI sorting table of the tag data information table is less than the set threshold ω, then the two reading times corresponding to the two RSSI signal values ​​are selected for comparison. When the number of readings of one of them is higher than the other by a set threshold σ (the number threshold σ is set to be related to the residence time, that is, when the inventory time / residence time of each antenna in the antenna array is 2000MS, the number threshold σ is set to 3 times, and can be subsequently adjusted based on the debugging and testing process and experience), the spatial point of the antenna number corresponding to the larger number of readings is selected as the positioning position of the tag; (5) If the difference between the two reading times is less than the set threshold σ, the spatial point of the optimal antenna number is output as the positioning position of the tag according to the RSSI signal value, the number of readings and the weighted total score of the spatial point of the antenna number in the two tag data information tables.

[0026] Furthermore, the weighted total score in step ⑤ is calculated according to the weight formula: weight (antenna number spatial point) × coefficient (antenna number spatial point) + weight (RSSI) × coefficient (RSSI) + weight (number of times read) × coefficient (number of times read) = total score, where weight (antenna number spatial point) > weight (RSSI) > weight (number of times read). The two tag data information tables are sorted by the total scores calculated according to the weight formula, and the spatial point of the antenna number in the tag data information table with the highest total score is selected as the tag positioning position. For example: Tag Tag1 is detected by three antennas Ant at the same time in a complete cycle. x ,Ant y ,Ant z After reading, sorted by RSSI value, they are (Ant x , RSSI x =-64.5, Cnt x =8, the spatial point is 8), (Ant y , RSSI y =-66.2, Cnt y =7, the spatial point is 10), (Ant z , RSSI z =-66.9, Cnt z =9, area number 7). The first place in each ranking gets 3 points, the second place gets 2 points, and the third place gets 1 point. Weighting coefficients: RSSI value is 0.3, number of times is 0.2, and position is 0.4. The scores and weighting coefficients can be set manually or based on experience; however, a more reliable approach is to train the BP neural network using a large number of data samples to determine these values. In actual debugging and testing, N sets of tests can be performed to select data with similar RSSI values ​​and number of times. The coefficients can then be inferred based on their true values. Multiple sets of data requiring weight calculation and their true results are selected and trained through the BP neural network to determine the scores and weighting coefficients. Neural network training techniques are common, so the training process will not be detailed here. Since the positioning algorithm described above reaches the point where differentiation based on the total weighted score is required, it indicates that comparing only RSSI values ​​and number of times is no longer a direct result. This comparison is based on the small differences in RSSI values ​​and number of times. Therefore, the highest weighting coefficient is assigned to position, followed by RSSI value and number of times. The position is determined by the distance from the middle position. Figure 3 It can be seen that spatial point 8 is closest to the center of the filing cabinet, followed by spatial point 9, and spatial point 7 is the last. Then:

[0027] Antx=3×0.3+2×0.2+3×0.4=2.5

[0028] Anty=2×0.3+1×0.2+2×0.4=1.6

[0029] Antz=1×0.3+3×0.2+1×0.4=1.3

[0030] Therefore, the optimal output result is that the area where Antx is located is 8.

[0031] According to the above-mentioned three-dimensional spatial model of the antenna array and the tag positioning algorithm, the precise location of the existing tag can be obtained. Since the antenna array has a wide range of uses, it can be used in the inventory of the entire cabinet, and can also be used in smart cabinets with multiple compartments to locate tags or objects. The difference between the two is that when the entire cabinet is inventoried, all antenna arrays need to be polled, so it takes a long time; and when a compartment of a smart cabinet with multiple compartments is opened separately, only the dual-feed point antenna corresponding to the compartment can be triggered for inventory, so the time period can be relatively short. When a single antenna is triggered to read the tag, if the tag is increased or decreased, it is only necessary to design a positioning logic algorithm based on the tag information read by the single antenna and the data information library of the original antenna array to obtain the increase or decrease of the tag. Specific description:

[0032] (1) The antenna numbers in the antenna array are distributed as Ant1, Ant2, Ant3...Antn

[0033] (2) The label data in the antenna array database is defined as:

[0034] Ant1 antenna number data: Ant1-Tag1, Ant1- Tag2,... Ant1- Tag m1

[0035] Ant2 antenna number data: Ant2- Tag1, Ant2- Tag2,... Ant2- Tag m2...

[0036] Antn antenna number data: Antn- Tag1, Antn- Tag2,... Antn- Tag mn

[0037] (3) During a tag data reading cycle of an antenna Antx in the antenna array, w tag data are read, named R1, R2, ..., Rw.

[0038] The first step is to determine whether Ri is in the Antx information library (Antx- Tag1, Antx- Tag2,... Antx-Tag m1 ):

[0039] If Ri is in the Antx repository, then Ri => status is unchanged;

[0040] If Ri is not in the Antx information library, check whether Ri is in all antenna array databases (Ant1-Antn). If it is in the database, it means that Ri is a tag in other antennas read in series, and Ri=>status remains unchanged; if Ri is not in the entire database, Ri=>is added;

[0041] Polling starts from R1 and ends at Rw.

[0042] The second step is to extract the tag data from the Antx database and record it as: Antx- Tag1, Antx-Tag2, Antx- Tag k,..., Antx- Tag mx;

[0043] Search Antx- Tag1, Antx- Tag2,..., Antx- Tag in R1-R30 in turn k,..., Antx-Tag mx ,

[0044] If you can find Antx- Tag in R1~R30 k , then Antx- Tag k =>The state has not changed;

[0045] If Antx- Tag is not found in R1~R30 k , then Antx- Tag k =>Take out;

[0046] Through the above comparative analysis, it can be concluded that after a single antenna reads the tags, it can accurately locate the newly added and removed tags.

[0047] Specific test results were verified: A smart file location cabinet (L×W×H = 900mm×475×1985mm) was used as the designated area. It was divided into 6 layers and 12 grids, with two standard circularly polarized UHF antennas deployed in each grid. Placing two antennas in each grid ensures that a pair of antennas creates a stronger field, minimizing missed reads when stacking RFID documents within the area.

[0048] The antenna uses a common near-field antenna in the scenario of antenna array positioning tag position. There are 12 grid areas, a total of 24 near-field antenna arrays. RFID files are placed in each area in turn, and the number of files is gradually increased. Inventory tests are performed. Each group of samples is tested 500 times. The test results are as follows:

[0049] When an average of 20 RFID documents are placed in each area, and the entire cabinet contains 240 RFID documents, the probability of a true cross-read exceeds 80%, and the probability of a missed read is 0.1%. Using only a simple RSSI value and a threshold comparison output, the cross-read rate exceeds 7.5%. Using the algorithm described in this article, the probability of a cross-read positioning result is less than 0.1%.

[0050] When an average of 30 RFID documents are placed in each area, and the entire cabinet contains 360 RFID documents, the probability of a true cross-read exceeds 76%, and the probability of a missed read is 0.2%. Using only a simple RSSI value and a threshold comparison output, the cross-read rate exceeds 5.1%. Using the algorithm described in this article, the cross-read probability of the positioning result is less than 0.1%.

[0051] When an average of 40 RFID documents are placed in each area, and the entire cabinet contains 480 RFID documents, the probability of a true cross-read exceeds 63%, and the probability of a missed read is less than 0.5%. Using only a simple RSSI value and a threshold comparison output, the cross-read rate exceeds 4.5%. Using the algorithm described in this article, the probability of a cross-read positioning result is less than 0.1%.

[0052] In the test data above, conventional circularly polarized antennas were used for tag counting. These antennas have high power and a wide coverage area, but each cabinet area cannot be completely shielded from signals. Consequently, cross-reading between different areas is very serious. As the number of RFID files increases, the missed read rate increases slightly, but cross-reading between different areas remains significant. Using only simple threshold comparison output for positioning results results in a high cross-read rate.

[0053] After adopting the positioning algorithm, the RSSI value and the number of times are combined with the spatial point model for comprehensive calculation, and the output correct positioning result has an accuracy rate of more than 99.9% and a cross-reading rate of less than 0.1%.

[0054] It can be seen from this that when the antenna array formed by the above antenna group is used in application scenarios such as file positioning / object positioning, the antenna itself cannot guarantee the uniformity of the field strength distribution of each antenna in the area, nor can it guarantee absolute shielding between the areas, so there is physical and obvious cross-reading between different areas. Only using the threshold value of comparing RSSI values ​​and times to output positioning results has the problem of high cross-reading rate. Using the positioning algorithm described in the present invention, it is possible to combine the spatial point model for comprehensive analysis, and the accuracy of the output positioning results is greatly improved.

[0055] The present invention is not limited to the above-mentioned specific embodiments. Those skilled in the art can implement the present invention in various other specific embodiments based on the contents disclosed in the present invention, or any simple changes or modifications made to the design structure and concept of the present invention fall within the scope of protection of the present invention.

Claims

1. A tag positioning method based on RFID technology, comprising the following steps: ① Arrange the antenna array module in the designated positioning area, partition the designated positioning area into multiple spatial positions, and number these spatial positions in sequence, which are called spatial points. Each antenna corresponds to a spatial point, and connect each antenna array to the antenna splitter of the RFID reader. ② After the RFID reader receives the command from the host computer to locate and inventory the items with RFID tags in the positioning area, it completes the data inventory of the tags in the positioning area, obtains the RSSI signal value of the tags in the positioning area each time they are inventoried, the number of times the tags are inventoried by each antenna per unit time, and the antenna number of each tag, and inputs them into the data processing module running on the host computer; it is characterized in that ③ the spatial point of each antenna in the antenna array is input into the antenna array three-dimensional space generation module in the data processing module to form a three-dimensional space model of the antenna array, in which the antenna is fed with antennas. ④ The RSSI signal value of each tag each time it is counted, the number of times each tag is counted by each antenna per unit time, and the antenna number of the tag counted are input into the tag data information table generation module in the data processing module to generate a tag data information table for each tag, and after sorting and calculating according to the strength of the RSSI signal value in the tag data information table, the tag data information table is ranked according to the RSSI value to obtain the RSSI ranking table of the tag data information table; ⑤ The tag positioning algorithm module in the data processing module performs tag positioning processing based on the advantages and disadvantages of the antenna's spatial point in the three-dimensional spatial model of the antenna array and the RSSI ranking table of the tag data information table, and then outputs the optimal antenna spatial point as the positioning position of the tag and transmits it to the host computer.

2. The tag positioning method based on RFID technology according to claim 1, characterized in that: In step ⑤, the tag positioning algorithm processing includes the following process: (1) if there is a tag data information table in which the RSSI signal value of the tag read by a certain antenna number and the ranking of the number of times the tag is read are both optimal, then the spatial point where the antenna number in the tag data information table is located is output as the positioning position of the tag; (2) If the RSSI signal value of a tag read by a certain antenna number and the number of times the tag is read are not optimal in the RSSI sorting table of the tag data information table, the optimal spatial point of the antenna number in the tag data information table is output as the positioning position of the tag according to the total weight of the RSSI signal value, the number of times the tag is read and the spatial point of the antenna number in the tag data information table.

3. The tag positioning method based on RFID technology according to claim 2, characterized in that: In step ⑤, if there is a situation where the RSSI signal value of the tag read by a certain antenna number exists in the RSSI sorting table of the tag data information table and the ranking of the number of times the tag is read is not optimal, then the two antenna numbers corresponding to the first two RSSI signal values ​​are selected from the RSSI sorting table of the tag data information table, and if the spatial point positions of the two antenna numbers are consistent, the spatial point positions of the antenna are output as the positioning position of the tag; if the spatial point positions of the two antenna numbers corresponding to the first two RSSI signal values ​​in the RSSI sorting table of the tag data information table are inconsistent, then when one of the RSSI signal values ​​is more than the set threshold value ω than the other RSSI signal value, the RSSI signal value with the larger value is selected. The corresponding antenna number spatial point is used as the positioning position of the tag; if the difference between the first two RSSI signal values ​​in the RSSI sorting table of the tag data information table is less than the set threshold ω, the two reading times corresponding to the two RSSI signal values ​​are selected for comparison. When the number of readings of one of them is higher than the other by a set threshold σ, the spatial point of the antenna number corresponding to the larger number of readings is selected as the positioning position of the tag; if the difference between the two reading times is less than the set threshold σ, the spatial point of the optimal antenna number is output as the positioning position of the tag according to the RSSI signal value, the number of readings and the weighted total score of the spatial point of the antenna number in the two tag data information tables.

4. The tag positioning method based on RFID technology according to claim 3, characterized in that: The weighted total score in step ⑤ is calculated according to the weight formula: weight (antenna number spatial point) × coefficient (antenna number spatial point) + weight (RSSI) × coefficient (RSSI) + weight (number of times read) × coefficient (number of times read) = total score, where weight (antenna number spatial point) > weight (RSSI) > weight (number of times read). The two tag data information tables are sorted by the total scores calculated according to the weight formula, and the spatial point where the antenna number in the tag data information table with the highest total score is located is selected as the tag positioning position.

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